---------------------------------------------------------------------------- S H O R E W A L L 4 . 4 . 20 Beta 4 ---------------------------------------------------------------------------- I. PROBLEMS CORRECTED IN THIS RELEASE II. KNOWN PROBLEMS REMAINING III. NEW FEATURES IN THIS RELEASE IV. RELEASE 4.4 HIGHLIGHTS V. MIGRATION ISSUES VI. PROBLEMS CORRECTED AND NEW FEATURES IN PRIOR RELEASES ---------------------------------------------------------------------------- I. P R O B L E M S C O R R E C T E D I N T H I S R E L E A S E ---------------------------------------------------------------------------- 1) Previously, when a device number was explicitly specified in /etc/shorewall/tcdevices, all unused numbers less than the one specified were unavailable for allocation to following entries that did not specify a number. Now, the compiler selects the lowest unallocated number when no device number is explicitly allocated. ---------------------------------------------------------------------------- I I. K N O W N P R O B L E M S R E M A I N I N G ---------------------------------------------------------------------------- 1) On systems running Upstart, shorewall-init cannot reliably secure the firewall before interfaces are brought up. ---------------------------------------------------------------------------- I I I. N E W F E A T U R E S I N T H I S R E L E A S E ---------------------------------------------------------------------------- 1) The implementation of the environmental variables LIBEXEC and PERLLIB that was introduced in 4.4.19 has been changed slightly. The installers now allow absolute path names to be supplied in these variables so that the executables and/or Perl modules may be installed under a top-level directory other than /usr. The change is compatible with 4.4.19 in that if a relative path name is supplied, then '/usr/' is prepended to the supplied name. 2) A new ACCOUNTING_TABLE option has been added to shorewall.conf and shorewall6.conf. The setting determines the Netfilter table (filter or mangle) where accounting rules are created. When ACCOUNTING_TABLE=mangle, the allowable accounting file sections are: PREROUTING INPUT OUTPUT FORWARD POSTROUTING Present sections must appear in that order. 3) An NFLOG 'ACTION' has been added to the accounting file to allow sending matching packets (or the leading part of them) to backend accounting daemons via a netlink socket. 4) A 'whitelist' option has been added to the blacklist file. When 'whitelist' is specified, packets/connections matching the entry are not matched against the entries which follow. No logging of whitelisted packets/connections is performed. 5) Support for the AUDIT target has been added. AUDIT is a feature of the 2.6.39 kernel and iptables 1.4.10 that allows security auditing of access decisions. The support involves the following: a) A new "AUDIT Target" capability is added and is required for auditing support. To use AUDIT support with a capabilities file, that file must be generated using this or a later release. Use 'shorewall show capabilities' after installing this release to see if your kernel and iptables support the AUDIT target. b) In /etc/shorewall/policy's POLICY column, the policy (and default action, if any) may be followed by ':audit' to cause applications of the policy to be audited. This means that any NEW connection that does not match any rule in the rules file or in the applicable 'default action' will be audited. Only ACCEPT, DROP and REJECT policies may be audited. Example: #SOURCE DEST POLICY LOG # LEVEL net fw DROP:audit It is allowed to also specify a log level on audited policies resulting in both auditing and logging. c) Three new builtin actions that may be used in the rules file, in macros and in other actions. A_ACCEPT - Audits and accepts the connection request A_DROP - Audits and drops the connection request A_REJECT - Audits and rejects A log level may be supplied with these actions to provide both auditing and logging. Example: A_ACCEPT:info loc net ... d) The BLACKLIST_DISPOSITION, MACLIST_DISPOSITION and TCP_FLAGS_DISPOSITION options may be set as follows: BLACKLIST_DISPOSITION A_DROP or A_REJECT MACLIST_DISPOSITION A_DROP A_REJECT, unless MACLIST_TABLE=mangle TCP_FLAGS_DISPOSITION A_DROP or A_REJECT e) A SMURF_DISPOSITION option has been added to shorewall.conf. The default value is DROP; if the option is set to A_DROP, then dropped smurfs are audited. f) An 'audit' option has been added to the /etc/shorewall/blacklist file which causes the packets matching the entry to be audited. 'audit' may not be specified together with 'whitelist'. g) The builtin actions (dropBroadcast, rejNonSyn, etc.) now support an 'audit' parameter which causes all ACCEPT, DROP and REJECTs performed by the action to be audited. This allows creation of audited versions of the Shorewall-provided default actions (action.Drop and action.Reject). Note: The builtin actions are those actions listed in the output of 'shorewall show actions' with names begin with a lower-case letter. Example: #ACTION SOURCE DEST rejNonSyn(audit) net all 6) Up to this release, the behaviors of 'start -f' and 'restart -f' has been inconsistent. The 'start -f' command compares the modification times of /etc/shorewall[6] with /var/lib/shorewall[6]/restore while 'restart -f' compares with /var/lib/shorewall[6]/firewall. To make the two consistent, a new LEGACY_FASTSTART option has been added. The default value when the option isn't specified is LEGACY_FASTSTART=Yes which preserves the old behavior. When LEGACY_FASTSTART=No, 'start -f' and 'restart -f' compare with /var/lib/shorewall[6]/firewall. 7) A '-c' (compile) option has been added to the 'restart' command in both Shorewall and Shorewall6. It overrides the setting of AUTOMAKE and unconditionally forces a recompilation of the configuration. When both -c and -f are specified, the result is determined by the option that appears last. ---------------------------------------------------------------------------- I V. R E L E A S E 4 . 4 H I G H L I G H T S ---------------------------------------------------------------------------- 1) Support for Shorewall-shell has been discontinued. Shorewall-perl has been combined with Shorewall-common to produce a single Shorewall package. 2) Support for the "Hierarchical Fair Service Curve" (HFSC) queuing discipline has been added. HFSC is superior to the "Hierarchical Token Bucket" queuing discipline where realtime traffic such as VOIP is being used. HTB remains the default queuing discipline. 3) Support for the "flow" traffic classifier has been added. This classifier can help prevent multi-connection applications such as BitTorrent from using an unfair amount of bandwidth. 4) The Shorewall documentation and man pages have been purged of information about earlier Shorewall releases. The documentation describes only the behavior of Shorewall 4.4 and later versions. 5) The interfaces file OPTIONs have been extended to largely remove the need for the hosts file. 6) It is now possible to define PREROUTING and OUTPUT marking rules that cause new connections to use the same provider as an existing connection of the same kind. 7) Dynamic Zone support is once again available for IPv4; ipset support is required in your kernel and in iptables. 8) A new AUTOMAKE option has been added to shorewall.conf and shorewall6.conf. Setting this option will allow Shorewall to skip the compilation phase during start/restart if no configuration changes have occurred since the last start/restart. 9) The LIMIT:BURST column in /etc/shorewall/policy (/etc/shorewall6/policy) and the RATE LIMIT column in /etc/shorewall/rules (/etc/shorewall6/rules) may now be used to limit on a per source IP or per destination IP basis. 10) Support for per-IP traffic shaping classes has been added. 11) Support for netfilter's TRACE facility has been added. TRACE allows you to trace selected packets through Netfilter, including marking by tcrules. 12) You may now preview the generated ruleset by using the '-r' option to the 'check' command (e.g., "shorewall check -r"). 13) A new simplified Traffic Shaping facility is now available. 14) Additional ruleset optimization options are available. 15) TPROXY support has been added. 16) Explicit support for Linux-vserver has been added. It is now possible to define sub-zones of $FW. 17) A 'Universal' sample configuration is now availale for a 'plug-and-play' firewall. 18) Support for the AUDIT iptables target has been added. ---------------------------------------------------------------------------- V. M I G R A T I O N I S S U E S ---------------------------------------------------------------------------- 1) If you are currently using Shorewall-shell: a) In shorewall.conf, if you have specified "SHOREWALL_COMPILER=shell" then you must either: - change that specification to "SHOREWALL_COMPILER=perl"; or - change that specification to "SHOREWALL_COMPILER="; or - delete the specification altogether. Failure to do so will result in the following warning: WARNING: SHOREWALL_COMPILER=shell ignored. Shorewall-shell support has been removed in this release. b) Review the migration issues at http://www.shorewall.net/LennyToSqueeze.html and make changes as required. We strongly recommend that you migrate to Shorewall-perl on your current Shorewall version before upgrading to Shorewall 4.4.0. That way, you can have both Shorewall-shell and Shorewall-perl available until you are certain that Shorewall-perl is working correctly for you. 2) The 'shorewall stop', 'shorewall clear', 'shorewall6 stop' and 'shorewall6 clear' commands no longer read the 'routestopped' file. The 'routestopped' file used is the one that was present at the last 'start', 'restart' or 'restore' command. IMPORTANT: If you modify the routestopped file, you must refresh or restart Shorewall before the changes to that file take effect. 3) The old macro parameter syntax (e.g., SSH/ACCEPT) is now deprecated in favor of the new syntax (e.g., SSH(ACCEPT)). The 4.4 documentation uses the new syntax exclusively, although the old syntax continues to be supported. The sample configurations also use the new syntax. 4) Support for the SAME target in /etc/shorewall/masq and /etc/shorewall/rules has been removed, following the removal of the underlying support in the Linux kernel. 5) Supplying an interface name in the SOURCE column of /etc/shorewall/masq is now deprecated. Entering the name of an interface there will result in a compile-time warning: WARNING: Using an interface as the masq SOURCE requires the interface to be up and configured when Shorewall starts/restarts To avoid this warning, replace interface names by the corresponding network(s) in CIDR format (e.g., 192.168.144.0/24). 6) Previously, Shorewall has treated traffic shaping class IDs as decimal numbers (or pairs of decimal numbers). That worked fine until IPMARK was implemented. IPMARK requires Shorewall to generate class Ids in numeric sequence. In 4.3.9, that didn't work correctly because Shorewall was generating the sequence "..8,9,10,11..." when the correct sequence was "...8,9,a,b,...". Shorewall now treats class IDs as hex, as do 'tc' and 'iptables'. This should only be an issue if you have more than 9 interfaces defined in /etc/shorewall/tcdevices and if you use class IDs in /etc/shorewall/tcrules or /etc/shorewall/tcfilters. You will need to renumber the class IDs for devices 10 and greater. 7) Support for the 'norfc1918' interface and host option has been removed. If 'norfc1918' is specified for an entry in either the interfaces or the hosts file, a warning is issued and the option is ignored. Simply remove the option to avoid the warning. Similarly, if RFC1918_STRICT=Yes or a non-empty RFC1918_LOG_LEVEL is given in shorewall.conf, a warning will be issued and the option will be ignored. You may simply delete the RFC1918-related options from your shorewall.conf file if you are seeing warnings regarding them. Users who currently use 'norfc1918' are encouraged to consider using NULL_ROUTE_RFC1918=Yes instead. 8) The install.sh scripts in the Shorewall and Shorewall6 packages no longer create a backup copy of the existing configuration. If you want your configuration backed up prior to upgrading, you will need to do that yourself. As part of this change, the fallback.sh scripts are no longer released. 9) In earlier releases, if an ipsec zone was defined as a sub-zone of an ipv4 or ipv6 zone using the special :,... syntax, CONTINUE policies for the sub-zone did not work as expected. Traffic that was not matched by a sub-zone rule was not compared against the parent zone(s) rules. In 4.4.0, such traffic IS compared against the parent zone rules. 10) The name 'any' is now reserved and may not be used as a zone name. 11) Perl module initialization has changed in Shorewall 4.4.1. Previously, each Shorewall Perl package would initialize its global variables for IPv4 in an INIT block. Then, if the compilation turned out to be for IPv6, Shorewall::Compiler::compiler() would reinitialize them for IPv6. Beginning in Shorewall 4.4.1, the modules do not initialize themselves in an INIT block. So if you use Shorewall modules outside of the Shorewall compilation environment, then you must explicitly call the module's 'initialize' function after the module has been loaded. 12) Checking for zone membership has been tighened up. Previously, a zone could contain :0.0.0.0/0 along with other hosts; now, if the zone has :0.0.0.0/0 (even with exclusions), then it may have no additional members in /etc/shorewall/hosts. 13) ADD_IP_ALIASES=No is now the setting in the released shorewall.conf and in all of the samples. This will not affect you during upgrade unless you choose to replace your current shorewall.conf with the one from the release (not recommended). 14) The names of interface configuration variables in generated scripts have been changed to insure uniqueness. These names now begin with SW_. This change will only affect you if your extension scripts are using one or more of these variables. Old Variable Name New Variable Name ----------------------------------------------------- iface_ADDRESS SW_iface_ADDRESS iface_BCASTS SW_iface_BCASTS iface_ACASTS SW_iface_ACASTS iface_GATEWAY SW_iface_GATEWAY iface_ADDRESSES SW_iface_ADDRESSES iface_NETWORKS SW_iface_NETWORKS iface_MAC SW_iface_MAC provider_IS_USABLE SW_provider_IS_USABLE where 'iface' is a capitalized interface name (e.g., ETH0) and 'provider' is the capitalized name of a provider. 15) Support for the OPTIONS column in /etc/shorewall/blacklist (/etc/shorewall6/blacklist) has been removed. Blacklisting by destination IP address will be included in a later Shorewall release. 16) If your /etc/shorewall/params (or /etc/shorewall6/params) file sends output to Standard Output, you need to be aware that the output will be redirected to Standard Error beginning with Shorewall 4.4.16. 17) Beginning with Shorewall 4.4.17, the EXPORTPARAMS option is deprecated. With EXPORTPARAMS=No, the variables set by /etc/shorewall/params (/etc/shorewall6/params) at compile time are now available in the compiled firewall script. ---------------------------------------------------------------------------- V I. P R O B L E M S C O R R E C T E D A N D N E W F E A T U R E S I N P R I O R R E L E A S E S ---------------------------------------------------------------------------- P R O B L E M S C O R R E C T E D I N 4 . 4 . 1 9 ---------------------------------------------------------------------------- 4.4.19.4 1) Previously, the compiler would allow a degenerate entry (only the BAND specified) in /etc/shorewall/tcpri. Such an entry now raises a compilation error. 2) Previously, it was possible to specify tcfilters and tcrules that classified traffic with the class-id of a non-leaf HFSC class. Such classes are not capabable of handling packets. Shorewall now generates a compile-time warning in this case. If a non-leaf class is specified as the default class, then Shorewall now generates a compile-time error since that configuration allows no network traffic to flow. 3) Traditionally, Shorewall has not checked for the existance of ipsets mentioned in the configuration, potentially resulting in a run-time start/restart failure. Now, the compiler will issue a WARNING if: a) The compiler is being run by root. b) The compilation isn't producing a script to run on a remote system under a -lite product. c) An ipset appearing in the configuration does not exist on the local system. 4) As previously implemented, the 'refresh' command could fail or could result in a ruleset other than what was intended. If there had been changes in the ruleset since it was originally started/restarted/restored that added or deleted sequenced chains (chains such as ~lognnn and ~exclnnn), the resulting ruleset could jump to the wrong such chains or could fail to 'refresh' successfully. This issue has been corrected as follows. When a 'refresh' is done and individual chains are involved, then each table that contains both sequenced chains and one of the chains being refreshed is refreshed in its entirety. For example, if 'shorwall refresh foo' is issued and the filter table (which is the default) contains any sequenced chains, then the entire table is reloaded. Note that this reload operation is atomic so no packets are passed through an inconsistent configuration. 5) When 'shorewall6 refresh' was run previously, a harmless 'ip6tables: Chain exists' message was generated. 4.4.19.3 1) The changes in 4.4.19.1 that corrected long-standing issues with default route save/restore were incompatible with 'gawk'. When 'gawk' was installed (rather than 'mawk'), awk syntax errors having to do with the symbol 'default' were issued. This incompatibility has been corrected. 2) Previously, an entry in the USER/GROUP column in the rules and tcrules files could cause run-time start/restart failures if the rule(s) being added did not have the firewall as the source (rules file) and were not being added to the POSTROUTING chain (:T designator in the tcrules file). This error is now caught by the compiler. 3) Shorewall now insures that a route to a default gateway exists in the main table before it attempts to add a default route through that gateway in a provider table. This prevents start/restart failures in the rare event that such a route does not exist. 4) CLASSIFY TC rules can apply to traffic exiting only the interface associated with the class-id specified in the first column. In a Multi-ISP configuration, a naive user might create this TC rule: 1:2 - 1.2.3.4 This will work fine when 1.2.3.4 can only be routed out of a single interface. However, if we assume that eth0 is interface 1, then the above rule only works for traffic leaving via eth0. Beginning with this release, the Shorewall compiler will interpret the above rule as this one: 1.2 - eth0:1.2.3.4 4.4.19.2 1) In Shorewall-shell, there was the ability to specify IPSET names in the ORIGINAL DEST column of DNAT and REDIRECT rules. That ability, inadvertently dropped in Shorewall-perl, has been restored. CAUTION: When an IPSET is used in this way, the server port is opened from the SOURCE zone. Example: DNAT net dmz:10.1.1.2 tcp 80 - +foo will implicitly add this rule ACCEPT net dmz:10.1.1.2 tcp 80 2) Several problems with complex TC have been corrected: a) The following entry in /etc/shorewall/tcclasses A:1 - 10*full/100:50ms 20*full/100 1 tcp-ack produced this error: ERROR: Unknown INTERFACE (A) : /etc/shorewall/tcclasses This has been corrected. b) Shorewall reserves class number 1 for the root class of the queuing discipline. Definining class 1 in /etc/shorewall/tcclasses was previoulsly escaping detection by the compiler, resulting in a run-time error. c) The compiler did not complain if a CLASSID specified in the MARK column of tcrules referred to an IFB class. Such a rule would be nonsensical since packets are passed through the IFB before they are passed through any marking rules. Such a configuration now results in a compilation error. d) Where there are more than 10 tcdevices, tcfilter entries could generate invalid rules. 3) Double exclusion involving ipset lists was previously not detected, resulting in anomalous behavior. Example: ACCEPT:info $FW net:!10.1.0.7,10.1.0.9,+[!my-host[src]]] Such cases now result in a compilation error. 4.4.19.1 1) A duplicate ACCEPT rule in the INPUT chain has been eliminated when the firewall is stopped. 2) A defect introduced in Shorewall 4.4.17 broke the ability to specify ':-' in the ADDRESS column of /etc/shorewall/masq. 3) Several long-standing defects having to do with default route save/restore have been corrected in the Multi-ISP implementation. a) Shorewall previously interpreted all 'nexthop' routes as default routes when analyzing the pre-start routing configuration. This could lead to unwanted default routes when the firewall was started or stopped. b) The default route with metric 0 was usually not restored during 'stop' processing. c) If there were multiple default routes in the main table prior to 'shorewall start' and USE_DEFAULT_RT was set, only the first one with metric 0 was deleted. 4.4.19 1) Corrected a problem in optimize level 4 that resulted in the following compile-time failure. Can't use an undefined value as an ARRAY reference at /usr/share/shorewall/Shorewall/Chains.pm line 862. 2) If a DNAT or REDIRECT rule applied to a source zone with an interface defined with 'physical=+', then the nat table 'dnat' chain might have been created but not referenced. This prevented the DNAT or REDIRECT rule from working correctly. 3) Previously, if a variable set in /etc/shorewall/params was given a value containing shell metacharacters, then the compiled script would contain syntax errors. 4) The pathname of the 'conntrack' binary was erroneously printed in the output of 'shorewall6 show connections'. 5) Correct a problem whereby incorrect Netfilter rules were generated when a bridge with ports was given a logical name. 6) If a bridge interface had subordinate ports defined in /etc/shorewall/interface, then an ipsec entry (either ipsec zone or the 'ipsec' option specified) in /etc/shorewall/hosts resulted in the compiler generating an incorrect Netfilter configuration. 7) Previously /var/log/shorewall*-init.log was created in the wrong Selinux context. The rpm's have been modified to correct that issue. 8) An issue with params processing on RHEL6 has been corrected. The problem manifested as the following type of warning: WARNING: Param line (export OLDPWD) ignored at /usr/share/shorewall/Shorewall/Config.pm line 2993. 9) A fatal error is now raised if '!0' appears in the PROTO column of files that have that column. This avoids an iptables-restore failure at run time. ---------------------------------------------------------------------------- N E W F E A T U R E S I N 4 . 4 . 1 9 ---------------------------------------------------------------------------- 1) When TC_ENABLED=Simple, ACK packets are now placed in the highest priority class. An ACK packet is a TCP packet with the ACK flag set and no data payload. Rationale: Entries in /etc/shorewall[6]/tcpri affect both incoming and outgoing connections. If a particular application, SMTP for example, is placed in priority class 3, then outgoing ACK packets for incoming email were previously placed in priority class 3 as well. This could have the effect of slowing down incoming mail when the goal was to give outgoing mail a lower priority. By unconditionally placing ACK packets in priority class 1, this issue is avoided. 2) Up to this point, the Perl-based rules compiler has not accepted ICMP type lists. This is in contrast to the shell-based compiler which did support such lists. Support for ICMP (and ICMPv6) type lists has now been restored. 3) Distributions have different philosophies about the proper file hierarchy. Two issures are particularly contentious: - Executable files in /usr/share/shorewall*. These include; getparams compiler.pl wait4ifup shorecap ifupdown - Perl Modules in /usr/share/shorewall/Shorewall. To allow distributions to designate alternate locations for these files, the installers (install.sh) now support the following environmental variables: LIBEXEC -- determines where in /usr getparams, compiler.pl, wait4ifup, shorecap and ifupdown are installed. Shorewall and Shorewall6 must be installed with the same value of LIBEXEC. The listed executables are installed in /usr/${LIBEXEC}/shorewall*. The default value of LIBEXEC is 'share'. LIBEXEC is recognized by all installers and uninstallers. PERLLIB -- determines where in /usr the Shorewall perl modules are installed. Shorewall and Shorewall6 must be installed with the same value of PERLLIB. The modules are installed in /usr/${PERLLIB}/Shorewall. The default value of PERLLIB is 'share/shorewall'. PERLLIB is only recognized by the Shorewall and Shorewall6 installers and the same value must be passed to both installers. 4) Bridge/ports handling has been significantly improved, resulting in packets to/from bridges traversing fewer rules. 5) A list of protocols is now permitted in the PROTO column of the rules file. 6) The contents of the Netfilter mangle table are now included in the output from 'shorewall show tc'. 7) Simple traffic shaping can now have a common configuration between IPv4 and IPv6. To do that: - Set TC_ENABLED=Simple in both /etc/shorewall/shorewall.conf and /etc/shorewall6/shorewall6.conf - Configure /etc/shorewall/tcinterfaces. - Leave /etc/shorewall6/tcinterfaces empty. - Configure /etc/shorewall/tcpri (if desired) - Configure /etc/shorewall6/tcpri (if desired) It should be noted that when IPv6 packets are encapsulated for transmission by 6to4/6in4, they retain their marks. ---------------------------------------------------------------------------- P R O B L E M S C O R R E C T E D I N 4 . 4 . 1 8 ---------------------------------------------------------------------------- 4.4.18 Final 1) Previously, if an IPv6 host address (no "/") was used in a context where a network address is allowed, the compiler failed to supply the default of 128. This could lead to startup errors and/or Perl errors such as: Use of uninitialized value $mask in concatenation (.) or string at /usr/share/shorewall/Shorewall/Tc.pm line 979, <$currentfile> line 11. 2) The option for the IN-BANDWIDTH column of tcdevices was previously not recognized. That functionality has been restored. 3) If an interface mentioned in the tcfilters file was not up when Shorewall was started or restarted, then the command would fail at run-time with a 'tc' error message. 4.4.18 RC 1 1) None. 4.4.18 Beta 4 1) Edting of the MARK column has been tighened to catch errors at compile time rather than at run time. 2) The MODULE_SUFFIX default has been changed to "ko ko.gz o o.gz gz" to get the most common suffixes at the front of the list. It is still recommended that you modify this setting to include only the suffix(es) used on your system. Current distributions use 'ko' almost exclusively. 4.4.18 Beta 2 1) Previously, the 'local' option in /etc/shorewall6/providers would produce an 'ip route add' command containing an IPv4 address. It now correctly uses the equivalent IPv6 address. Note that this option is still undocumented for use with IPv6. 2) When optimize level 4 was set, the optimizer mis-handled rules of the form: -A -j -m comment ... when such a rule was the only rule in a chain. 4.4.18 Beta 1 None. ---------------------------------------------------------------------------- N E W F E A T U R E S I N 4 . 4 . 1 8 ---------------------------------------------------------------------------- 1) The modules files are now just a driver that INCLUDEs several new files and one old file: - /usr/share/shorewall[6]/modules.essential # Essential modules - /usr/share/shorewall[6]/modules.xtables # xt_ modules - /usr/share/shorewall[6]/helpers # Existing file - /usr/share/shorewall/ipset # ipset modules - /usr/share/shorewall[6]/modules.tc # Traffic Shaping - /usr/share/shorewall[6]/modules.extensions # Other extensions This should make it easier to configure your own /etc/shorewall[6]/modules file that won't be obsolete when you upgrade your Shorewall/Shorewall6 installation. For example, if you don't use traffic shaping or ipsets, you can remove those from your copy of the modules file (copy in /etc/shorewall/). 2) Traditionally, the root of the Shorewall accounting rules has been the 'accounting' chain. Having a single root chain has drawbacks: - Many rules are traversed needlessly (they could not possibly match traffic). - At any time, the Netfilter team could begin generating errors when loading those same rules. - MAC addresses may not be used in the accounting rules. - The 'accounting' chain cannot be optimized when OPTIMIZE_ACCOUNTING=Yes. In addition, currently the rules may be defined in any order so the rules compiler must post-process the ruleset to alert the user to unreferenced chains. Beginning with Shorewall 4.4.18, the accounting structure can be created with three root chains: - accountin: Rules that are valid in the INPUT chain (may not specify an output interface). - accountout: Rules that are valid in the OUTPUT chain (may not specify an input interface or a MAC address). - accountfwd: Other rules. The new structure is enabled by sectioning the accounting file in a manner similar to the rules file. The sections are INPUT, OUTPUT and FORWARD and must appear in that order (although any of them may be omitted). The first non-commentary record in the accounting file must be a section header when sectioning is used. When sections are enabled: - You must jump to a user-defined accounting chain before you can add rules to that chain. This eliminates the possibility of unreferenced chains. - You may not specify an output interface in the INPUT section. - In the OUTPUT section: - You may not specify an input interface - You may not jump to a chain defined in the INPUT section that specifies an input interface - You may not specify a MAC address - You may not jump to a chain defined in the INPUT section that specifies specifies a MAC address. - The default value of the CHAIN column is: - 'accountin' in the INPUT section - 'accountout' in the OUTPUT section - 'accountfwd' in the FORWARD section - Traffic addressed to the firewall goes through the rules defined in the INPUT section. - Traffic originating on the firewall goes through the rules defined in the OUTPUT section. - Traffic being forwarded through the firewall goes through the rules defined in the FORWARD section. As part of this change, the USER/GROUP column must now be empty except in the OUTPUT section. This is consistent with recent Netfilter releases which disallow the owner match in rules reachable from the INPUT and FORWARD hooks. 3) Internals Change: The Policy.pm module has been merged into the Rules.pm module. ---------------------------------------------------------------------------- P R O B L E M S C O R R E C T E D I N 4 . 4 . 1 7 ---------------------------------------------------------------------------- 1) Previously, Shorewall did not check the length of the names of accounting chains and manual chains. This could result in errors when loading the resulting ruleset. Now, the compiler issues an error for chain names longer than 29 characters. Additionally, the compiler now ensures that these chain names are composed only of letters, digits, underscores ('_') and dashes ("-"). This eliminates Perl runtime errors or other failures when a chain name is embedded within a regular expression. 2) Several issues with complex traffic shaping have been resolved: a) Specifying IPv6 network addresses in the SOURCE or DEST columns of /etc/shorewall6/tcfilters now works correctly. Previously, Perl runtime warnings occurred and an invalid tc command was generated. b) Previously, if flow= was specified on a parent class, a perl runtime warning occurred and an invalid tc command was generated. This combination is now flagged as an error at compile time. c) There is now an ipv6 tcfilters skeleton included with Shorewall6. 3) Several issues with accounting are corrected. a) If an accounting rule of the form: chain1 chain2 was configured and neither chain was referenced again in the configuration, then an internal error was generated when optimize level 4 was selected and OPTIMIZE_ACCOUNTING=Yes. b) If there was only a single accounting rule and that rule specified an interface in the SOURCE or DEST columns, then the generated ruleset would fail to load when OPTIMIZE_ACCOUNTING=Yes. c) If a per-IP accounting table name appeared in more than one rule and the specified network was not the same in all occurrences, then the generated ruleset would fail to load. This is now flagged as an error at compile time. 4) Two defects in compiler module loading have been corrected: a) Previously, the kernel/net/ipv6/netfilter/ directory was not searched. b) A Perl diagnostic was issued when running on a monolithic kernel when the modutils package was installed. 5) A line containing only 'INCLUDE' appearing in an extension script now generates a compile-time diagnostic rather than a run-time diagnostic. 6) Previously, the uninstall.sh scripts used insserv (if installed) on Debian-based systems. These scripts now use the preferred tool (updaterc.d). 7) Beginning with 4.4.16, compilation would fail if an empty shell variable was referenced in a config file on a system where /bin/sh is the Bourne Again Shell (bash). 8) In earlier versions. if OPTIMIZE=8 then the ruleset displayed by 'check -r' was the same as when OPTIMIZE=0 (unoptimized). Similarly, if OPTIMIZE=9 then the ruleset displayed was the same as when OPTIMIZE=1. 9) Startup could previously fail on a system where kernel module autoloading was not available and where TC_ENABLED=Simple was specified in shorewall.conf or shorewall6.conf. 10) Previously, a 'done.' message could be printed at the end of command processing even when the command had failed. Now, such a message only appears if the command completed successfully. ---------------------------------------------------------------------------- N E W F E A T U R E S I N 4 . 4 . 1 7 ---------------------------------------------------------------------------- 1) This release adds support for per-IP accounting using the ACCOUNT target. That target is only available when xtables-addons is installed. This support has been successfully tested with xtables-addons 1.32 on: - Fedora 14 - Debian Squeeze - OpenSuSE 11.3 It has also been tested with xtables-addons 1.21 on: - Debian Lenny Information about xtables-addons installation may be found at http://www.shorewall.net/Dynamic.html#xtables-addons This feature required addition of the "ACCOUNT Target" capability so if you use a capabilities file, you will want to refresh it after installing this release. Per-IP accounting is configured in /etc/shorewall/accounting (it is not currently supported in IPv6). In the ACTION column, enter: ACCOUNT(,) where:
is the name of an accounting table (you choose the name). Rules specifying the same table will have their per-IP counters accumulated in that table. is an IPv4 in CIDR format. May be as large as a /8. Example: Suppose your WAN interface is eth0 and your LAN interface is eth1 with network 172.20.1.0/24. To account for all traffic between the WAN and LAN interfaces: #ACTION TABLE SOURCE DEST ... ACCOUNT(net-loc,172.20.1.0/24) - eth0 eth1 ACCOUNT(net-loc,172.20.1.0/24) - eth0 eth1 This will create a net-loc table for counting packets and bytes for traffic between the two interfaces. The table is dumped using the iptaccount utility: iptaccount [-f] -l net-loc Example (output folded): gateway:~# iptaccount -l loc-net libxt_ACCOUNT_cl userspace accounting tool v1.3 Showing table: loc-net Run #0 - 3 items found IP: 172.20.1.105 SRC packets: 115 bytes: 131107 DST packets: 68 bytes: 20045 IP: 172.20.1.131 SRC packets: 47 bytes: 12729 DST packets: 38 bytes: 25304 IP: 172.20.1.145 SRC packets: 20747 bytes: 2779676 DST packets: 27050 bytes: 32286071 Finished. gateway:~# For each local IP address with non-zero counters, the packet and byte count for both incoming traffic (IP is DST) and outgoing traffic (IP is SRC) are listed. The -f option causes the table to be flushed (reset all counters to zero). For a command synopsis, type: iptaccount --help One nice feature of per-IP accounting is that the counters survive 'shorewall restart'. This has a downside, however. If you change the associated with an accounting table, then you must "shorewall stop; shorewall start" to have a successful restart (counters will be cleared). 2) A 'show ipa' command has been added to /sbin/shorewall. It displays each per-IP accounting table. 3) Traditionally, the -lite products have used the modules (or helpers) file on the firewall system unless there is a modules (or helpers) file in the configuration directory on the administrative system. This release introduces the EXPORTMODULES option in shorewall[6].conf. When EXPORTMODULES=Yes, the modules (helpers) file on the administrative system will be used to determine the set of modules loaded. As part of this change, the modules and helpers files are now secured for read access by non-root users. 4) Given that shell variables are expanded at compile time, there was previously no way to cause such variables to be expanded at run time. This made it difficult (to impossible) to include dynamic IP addresses in a Shorewall-lite configuration. This release implements "Run-time address variables". In configuration files, these variables are expressed using an apersand ('&') followed by the name of an interface defined in /etc/shorewall/interfaces. Wild-card interfaces (those whose names end in '+') are not allowed to be used in this way. Example: ð0 would represent the primary IP address of eth0. Run-time address variables may be used in the SOURCE and DEST column of the following configuration files: accounting action files blacklist macro files rules tcrules tos They may also appear in the ORIGINAL DEST column of action files macro files rules They may also be used in the SOURCE and ADDRESS columns of the masq file. For optional interfaces, if the interface is not usable at the time that the firewall starts, the resulting Netfilter rule(s) containing the interface address are not added. 5) The shell variables set in /etc/shorewall/params (/etc/shorewall6/params) are now available in the compiled script at run-time with EXPORTPARAMS=No. The EXPORTPARAMS option is now deprecated and the released /etc/shorewall/shorewall.conf and /etc/shorewall/shorewall6.conf have been modified to specify EXPORTPARAMS=No. 6) The INCLUDE directive may now be used in the following extension scripts: clear findgw init isusable refresh refreshed restored start started stop stopped tcclear The directive is executed during compilation so that the INCLUDEd file(s) is(are) copied into the generated script. This same technique is also now used for INCLUDE directives in the params file when EXPORTPARAMS=Yes. Previously, INCLUDE directives in that file were strongly discouraged with EXPORTPARAMS=Yes because the INCLUDE was performed on the firewall system rather than on the administrative system. ---------------------------------------------------------------------------- P R O B L E M S C O R R E C T E D I N 4 . 4 . 1 6 ---------------------------------------------------------------------------- 1) If the output of 'env' contained a multi-line value, then compilation failed with an Internal Error. The code has been changed so that the compiler now handles multi-line values correctly. 2) In 4.4.15, output to Standard Out (FD 1) generated by /etc/shorewall/params (/etc/shorewall6/params) was redirected to /dev/null. It is now redirected to Standard Error (FD 2). 3) 2) If a params file did not appear in the CONFIG_PATH, compilation failed with the error: .: 31: Can't open /etc/shorewall6/params ERROR: Processing of /etc/shorewall6/params failed 4) Compilation no longer fails when /bin/sh is an older (e.g., RHEL5.x) bash. 5) Previously, proxy ARP with logical interface names did not work. Symptoms included numerous Perl runtime error messages. 6) Previously, the root of a wildcard name erroneously matched that name. For example 'eth' matched 'eth+'. Now there must be at least one additional character (e.g., 'eth4'). 7) Use of logical interface names in the notrack and ecn files resulted in perl runtime warning messages. 8) The use of wildcard-matching names in certain contexts would result in anomalous behavior. Among the symptoms were: - Perl run-time messages similar to this one: Use of uninitialized value in numeric comparison (<=>) at /usr/share/shorewall/Shorewall/Zones.pm line 1334. - Failure to treat the interface as optional or required. 9) Where two ISPs share the same interface, if one of the ISPs was not reachable, an iptables-restore error such as this occurred: iptables-restore v1.4.10: Bad mac address "-j" 10) Previously, under very rare circumstances, a chain would be optimized away while there were still jumps to the chain. This caused Shorewall start/restart to fail during iptables-restore. 11) Previously, the setting of BLACKLIST_DISPOSITION was not validated. Now, an error is raised unless the value is DROP or REJECT. ---------------------------------------------------------------------------- N E W F E A T U R E S I N 4 . 4 . 1 6 ---------------------------------------------------------------------------- 1) Shorewall-init now handles ppp devices. 2) To support proxy NDP in a manner similar to Proxy ARP, an /etc/shorewall6/proxyndp file has been added. It should be noted that IPv6 implements a "strong host model" whereas Linux IPv4 implements a "weak host model". In the strong model, IP addresses are associated with interfaces; in the weak model, they are associated with the host. This is relevant with respect to Proxy NDP in that a multi-homed Linux IPv6 host will only respond to neighbor discoverey requests for IPv6 addresses configured on the interface receiving the request. So if eth0 has address 2001:470:b:227::44/128 and eth1 has address 2001:470:b:227::1/64 then in order for eth1 to respond to neighbor discovery requests for 2001:470:b:227::44, the following entry in /etc/shorewall6/proxyndp is required: #ADDRESS INTERFACE EXTERNAL HAVEROUTE PERSISTENT 2001:470:b:227::44 - eth1 Yes As part of this change, the INTERFACE column in /etc/shorewall/proxyarp is now optional and is only required when HAVEROUTE=No (the default). 3) Shorewall 4.4.16 introduces format-2 Actions. Based on the similar feature of macros, format-2 actions allow the same column layout for macros, actions and rules. In the action.xxx file, simply make the first non-commentary line: FORMAT 2 This allows the lines which follow to have the same columns as those in the rules file. As part of this change, the earlier kludgy restrictions regarding Macros and Actions have been eliminated. For example, DNAT, DNAT-, REDIRECT, REDIRECT- and ACCEPT+ rules are now allowed in Actions and in macros invoked from Actions. Additionally, Macros used in Actions are now free to invoke other actions. 4) Action processing has been largely re-implemented in this release. The prior implementation contained a lot of duplicated code which made maintainance difficult. The old implementation pre-processed all action files early in the compilation process and then post-processed the ones that had been actionally used after the rules file had been read. The new algorithm generates the chain for each unique action invocation at the time that the invocation is encountered in the rules file. Consideration was given to eliminating the /usr/share/shorewall/actions.std and /etc/shorewall/actions files, since it is possible to discover actions "on the fly" in the same way as macros are discovered. That change was ultimately rejected because it could cause migration issues for users with macros and actions with the same name (e.g., action.xxx and macro.xxx). If a new major release of Shorewall (e.g., 4.6) is created, that change will be reconsidered for inclusion at that time. Action names are now verified to be composed of alphanumeric characters, '_' and '-'. There is now support for parameterized actions. The parameters are a comma-separated list enclosed in parentheses following the action name (e.g., ACT(REDIRECT,192.168.1.4)). Within the action body, the parameter values are available in $1, $2, etc. You can 'omit' a parameter in the list by using '-' (e,g, REDIRECT,-.info) would omit the second parameter (within the action body, $2 would expand to nothing). If you want to specify '-' as a parameter value, use '--'. Parameter values are also available to extensions scripts. See http://www.shorewall.net/Actions.html#Extension for more information. ---------------------------------------------------------------------------- P R O B L E M S C O R R E C T E D I N 4 . 4 . 1 5 ---------------------------------------------------------------------------- 1) Previously, if a) syn flood protection was enabled in a policy that specified 'all' for the SOURCE or DEST, and b) there was only one pair of zones matching that policy, and c) PROPAGATE_POLICIES=Yes in shorewall.conf, and d) logging was specified on the policy then the chain implementing the chain had "all" in its name while the logging rule did not. Example On a simple standalone configuration, /etc/shorewall/policy has: #SOURCE DEST POLICY LOGGING net all DROP info then the chain implementing syn flood protection would be named @net2all while the logging rule would indicate net2fw. Now, the chain will be named @net2fw. 2) If the current environment exported the VERBOSE variable with a non-zero value, then startup would fail. 3) If a route existed for an entire RFC1918 subnet (10.0.0.0/8, 172.20.0.0/12 or 192.168.0.0/16), then setting NULL_ROUTE_RFC1918=Yes would cause the route to be replaced with an 'unreachable' one. 4) Shorewall6 failed to start correctly if all the following were true: - Shorewall was installed using the tarball. It may have subsequently been installed using a distribution-specific package or the rpm from shorewall.net without first unstalling the tarball components. - Shorewall6 was installed using a distribution-specific package or the rpm from shorewall.net. - The file /etc/shorewall6/init was not created. 5) If an interface with physical='+' is given the 'optional' or 'required' option, then invalid shell variables names were generated by the compiler. 6) The contributed macro macro.JAP generated a fatal error when used. The root cause was a defect in parameter processing in nested macros (if 'PARAM' was passed to an nested macro invocation, it was not expanded to the current parameter value). 7) Previously, if find_first_interface_address() failed when running shorewall-lite or shoreawll6-lite, the following unhelpful message was issued: /usr/share/shorewall-lite/lib.common: line 449: startup_error: command not found ---------------------------------------------------------------------------- N E W F E A T U R E S I N 4 . 4 . 1 5 ---------------------------------------------------------------------------- 1) Munin and Squid macros have been contributed by Tuomo Soini. 2) The Shorewall6 accounting, tcrules and rules files now include a HEADERS column which allows matching based on the IPv6 extension and protocol headers included in a packet. The contents of the column are: [any:|exactly:]
where
is a comma-separated list of headers from the following: Long Name Short Name Number -------------------------------------- auth ah 51 esp esp 50 hop-by-hop hop 0 route ipv6-route 41 frag ipv6-frag 44 none ipv6-nonxt 59 protocol proto 255 If 'any:' is specified, the rule will match if any of the listed headers are present. If 'exactly:' is specified, the will match packets that exactly include all specified headers. If neither is given, 'any:' is assumed. This change adds a new capability (Header Match) so if you use a capabilities file, you will need to regenerate using this release. 3) It is now possible to add explicit routes to individual provider routing tables using the /etc/shorewall/routes (/etc/shorewall6/routes) file. See the shorewall-routes (5) and/or the shorewall6-routes (5) manpage. 4) Previously, /usr/share/shorewall/compiler.pl expected the contents of the params file to be passed in the environment. Now, the compiler invokes a small shell program (/usr/share/shorewall/getparams) to process the file and to pass the (variable,value) pairs back to the compiler. Shell variable expansion uses the value from the params file if the parameter was set in that file. Otherwise the current environment is used. If the variable does not appear in either place, an error message is generated. 5) Shared IPv4/IPv6 traffic shaping configuraiton is now available. The device and class configuration can be included in either the Shorewall or the Shorewall6 configuration. To place it in the Shorewall configuration: a) Set TC_ENABLED=Internal in shorewall.conf b) Set TC_ENABLED=Shared in shorewall6.conf c) Create symbolic link /etc/shorewall6/tcdevices pointing to /etc/shorewall/tcdevices. d) Create symbolic link /etc/shorewall6/tcclasses pointing to /etc/shorewall/tcclasses. e) Entries for both IPv4 and IPv6 can be included in /etc/shorewall/tcfilters. This file has been extended to allow both IPv4 and IPv6 entries to be included in a single file. f) Packet marking rules are included in both configurations' tcrules file as needed. CLASSIFY rules in /etc/shorewall6/tcrules are validated against the Shorewall TC configuration. In this setup, the tcdevices and tcclasses will only be updated when Shorewall is restarted. The IPv6 marking rules are updated when Shorewall6 is restarted. The above configuration may be reversed to allow Shorewall6 to control the TC configuration. ---------------------------------------------------------------------------- P R O B L E M S C O R R E C T E D I N 4 . 4 . 1 4 ---------------------------------------------------------------------------- 1) Previously, messages to the STARTUP_LOG had inconsistent date formats. 2) The blacklisting change in 4.4.13 was broken in some simple configurations with the effect that blacklisting was not enabled. 3) Previously, Shorewall6 produced an untidy sequence of error messages when an attempt was made to start it on a system running a kernel older than 2.6.24: [root@localhost shorewall6]# shorewall6 start Compiling... Processing /etc/shorewall6/shorewall6.conf... Loading Modules... Compiling /etc/shorewall6/zones... ... Shorewall configuration compiled to /var/lib/shorewall6/.start ERROR: Shorewall6 requires Linux kernel 2.6.24 or later /usr/share/shorewall6/lib.common: line 73: [: -lt: unary operator expected ERROR: Shorewall6 requires Linux kernel 2.6.24 or later [root@localhost shorewall6]# This has been corrected so that a single ERROR message is generated. 4) Previously, an ipset name appearing in the /etc/shorewall/hosts file could be qualified with a list of 'src' and/or 'dst' enclosed in quotes. This was virtually guaranteed not to work since the set must match when used to verify both a packet source and a packet destination. Now, the following error is raised: ERROR: ipset name qualification is disallowed in this file As part of this change, the ipset name is now verified to begin with a letter and be composed of letters, digits, underscores ("_") and hyphens ("-"). 5) The Shorewall-lite and Shorewall6-lite Debian init scripts contained a syntax error. 6) If the -v or -q options were used in /sbin/shorewall-lite or /sbin/shorewall6-lite commands that involve the compiled firewall script and the resulting effective VERBOSITY was > 2 or < -1, then the command would fail. 7) The log reading commands (show log, logwatch, and dump) returned no log records when run on one of the -lite products. 8) To avoid future confusion, the following obsolete options have been deleted from the sample shorewall.conf files: BRIDGING DELAYBLACKLISTLOAD PKTTYPE They will still be recognized by the rules compiler. 9) All sample .conf files have been changed to specify FORWARD_CLEAR_MARK= rather than FORWARD_CLEAR_MARK=Yes That way, systems without MARK support will still be able to install the sample configurations and FORWARD_CLEAR_MARK will default to Yes on systems with MARK support. 10) The install scripts in the tarballs now correctly create init symlinks on recent Ubuntu releases. 11) Previously, this entry in the OPTIONS column of /etc/shorewall/interfaces incorrectly generated a syntax error. nets=(1.2.3.0/24) The error was: ERROR: Invalid VLSM (24)) 12) Previously, if 10 or more interfaces were configured in Complex Traffic Shaping (/etc/shorewall/tcdevices), the following compilation diagnostic was generated: Argument "a" isn't numeric in sprintf at /usr/share/shorewall/Shorewall/Config.pm line 893. and an invalid TC configuration was generated. 13) If the current environment exported the VERBOSITY variable with a non-zero value, startup would fail. ---------------------------------------------------------------------------- N E W F E A T U R E S I N 4 . 4 . 1 4 ---------------------------------------------------------------------------- 1) Multiple source or destination ipset matches can be generated by enclosing the ipset list in +[...]. Example (/etc/shorewall/rules): ACCEPT $FW net:+[dest-ip-map,dest-port-map] 2) Shorewall now uses the 'conntrack' utility for 'show connections' if that utility is installed. Going forward, the Netfilter team will be enhancing this interface rather than the /proc interface. 3) The CPU time required for optimization has been reduced by 2/3. 4) An 'scfilter' extension script has been added. This extension script differs from other such scripts in that it is invoked by the command line tools (/sbin/shorewall, /sbin/shorewall6, /sbin/shorewall-lite and /sbin/shorewall6-lite). The script acts as a filter for the output of the 'show connections' command. Each connection is piped through the filter which can modify and/or drop information as desired. Example: #!/bin/sh sed 's/secmark=0 //' That script will remove 'secmark=0 ' from each line. The default script is: #!/bin/sh cat - which passes the output through unmodified. If you are using Shorewall-lite and/or Shorewall6-lite, the scfilter file is kept on the administrative system. The compiler encapsulates the script into a shell function that is copied into the generated auxillary configuration file (firewall.conf). That function is then invoked by the 'show connections' command. ---------------------------------------------------------------------------- P R O B L E M S C O R R E C T E D I N 4 . 4 . 1 3 ---------------------------------------------------------------------------- 1) Under rare circumstances where COMMENT is used to attach comments to rules, OPTIMIZE 8 through 15 could result in invalid iptables-restore (ip6tables-restore) input. 2) Under rare circumstances involving exclusion, OPTIMIZE 8 through 15 could result in invalid iptables-restore (ip6tables-restore) input. 3) The change in 4.4.12 to detect and use the new ipset match syntax broke the ability to detect the old ipset match capability. Now, both versions of the capability can be correctly detected. 4) Previously, if REQUIRE_INTERFACE=Yes then start/restart would fail if the last optional interface tested was not available. 5) Exclusion in the blacklist file was correctly validated but was then ignored when generating iptables (ip6tables) rules. 6) Previously, non-trivial exclusion (more than one excluded address/net) in CONTINUE, NONAT and ACCEPT+ rules generated valid but incorrect iptables input. This has been corrected but requires that your iptables/kernel support marking rules in any Netfilter table (CONTINUE in the tcrules file does not require this support). This fix implements a new 'Mark in any table' capability; those who utilize a capabilities file should re-generate the file using this release. 7) Interface handling has been extensively modified in this release to correct a number of problems with the earlier implementation. Among those problems: - Invalid shell variable names could be generated in the firewall script. The generated firewall script uses shell variables to track the availability of optional and required interfaces and to record detected gateways, detected addresses, etc. - The same shell variable name could be generated by two different interface names. - Entries in the interfaces file with a wildcard physical name (physical name ends with "+") and with the 'optional' option were handled strangely. o If there were references to specific interfaces that matched the wildcard, those entries were handled as if they had been defined as optional in the interfaces file. o If there were no references matching the wildcard, then the 'optional' option was effectively ignored. The new implementation: - Insures valid shell variable names. - Insures that shell variable names are unique. - Handles interface names appearing in the INTERFACE column of the providers file as a special case for 'optional'. If the name matches a wildcard entry in the interfaces file then the usability of the specific interface is tracked individually. - Handles the availabilty of other interfaces matching a wildcard as a group; if there is one useable interface in the group then the wildcard itself is considered usable. The following example illustrates this use case: /etc/shorewall/interfaces net ppp+ - optional /etc/shorewall/shorewall.conf REQUIRE_INTERFACE=Yes If there is any usable PPP interface then the firewall will be allowed to start. Previously, the firewall would never be allowed to start. 8) When a comma-separated list of 'src' and/or 'dst' was specified in an ipset invocation (e.g., "+fooset[src,src]), all but the first 'src' or 'dst' was previously ignored when generating the resulting iptables rule. 9) Beginning with Shorewall 4.4.9, the SAME target in tcrules has generated invalid iptables (ip6tables) input. That target now generates correct input. 10) Ipsets associated with 'dynamic' zones were being created during 'restart' but not during 'start'. 11) To work around an issue in Netfilter/iptables, Shorewall now uses state match rather than conntrack match for UNTRACKED state matching. 12) If the routestopped files contains NOTRACK rules, 'shorewall* clear' did not clear the raw table. 13) An error message was incorrectly generated if a port range of the form : (e.g., :22) appeared. 14) An error message is now generated when '*' appears in an interface name. ---------------------------------------------------------------------------- N E W F E A T U R E S I N 4 . 4 . 1 3 ---------------------------------------------------------------------------- 1) Entries in the rules file (both Shorewall and Shorewall6) may now contain zone lists in the SOURCE and DEST column. A zone list is a comma-separated list of zone names where each name appears in the zones file. A zone list may be optionally followed by a plus sign ("+") to indicate that the rule should apply to intra-zone traffic as well as to inter-zone traffic. Zone lists behave like 'all' and 'any' with respect to Optimization 1. If the rule matches the applicable policy for a given (source zone, dest zone), then the rule will be suppessed for that pair of zones unless overridden by the '!' suffix on the target in the ACTION column (e.g., ACCEPT!, DROP!:info, etc.). Additionally, 'any', 'all' and zone lists may be qualified in the same way as a single zone. Examples: fw,dmz:90.90.191.120/29 all:+blacklist The 'all' and 'any' keywords now support exclusion in the form of a comma-separated list of excluded zones. Examples: all!fw (same as all-). any+!dmz,loc (All zones except 'dmz' and 'loc' and include intra-zone rules). 2) An IPSEC column has been added to the accounting file, allowing you to segregate IPSEC traffic from non-IPSEC traffic. See 'man shorewall-accounting' (man shorewall6-accounting) for details. With this change, there are now three trees of accounting chains: - The one rooted in the 'accounting' chain. - The one rooted in the 'accipsecin' chain. This tree handles traffic that has been decrypted on the firewall. Rules in this tree cannot specify an interface name in the DEST column. - The one rooted in the 'accipsecout' chain. This tree handles traffic that will be encrypted on the firewall. Rules in this tree cannot specify an interface name in the SOURCE column. In reality, when there are bridges defined in the configuration, there is a fourth tree rooted in the 'accountout' chain. That chain handles traffic that originates on the firewall (both IPSEC and non-IPSEC). This change also implements a couple of new warnings: - WARNING: Adding rule to unreferenced accounting chain The first reference to user-defined accounting chain is not a JUMP or COUNT from an already-defined chain. - WARNING: Accounting chain has o references The named chain contains accounting rules but no JUMP or COUNT specifies that chain as the target. 3) Shorewall now supports the SECMARK and CONNSECMARK targets for manipulating the SELinux context of packets. See the shorewall-secmarks and shorewall6-secmarks manpages for details. As part of this change, the tcrules file now accepts $FW in the DEST column for marking packets in the INPUT chain. 4) Blacklisting has undergone considerable change in Shorewall 4.4.13. a) Blacklisting is now based on zones rather than on interfaces and host groups. b) Near compatibility with earlier releases is maintained. c) The keywords 'src' and 'dst' are now preferred in the OPTIONS column in /etc/shoreawll/blacklist, replacing 'from' and 'to' respectively. The old keywords are still supported. d) The 'blacklist' keyword may now appear in the OPTIONS, IN_OPTIONS and OUT_OPTIONS fields in /etc/shorewall/zones. i) In the IN_OPTIONS column, it indicates that packets received on the interface are checked against the 'src' entries in /etc/shorewall/blacklist. ii) In the OUT_OPTIONS column, it indicates that packets being sent to the interface are checked against the 'dst' entries. iii) Placing 'blacklist' in the OPTIONS column is equivalent to placing in in both the IN_OPTIONS and OUT_OPTIONS columns. e) The 'blacklist' option in the OPTIONS column of /etc/shorewall/interfaces or /etc/shorewall/hosts is now equivalent to placing it in the IN_OPTIONS column of the associates record in /etc/shorewall/zones. If no zone is given in the ZONE column of /etc/shorewall/interfaces, the 'blacklist' option is ignored with a warning (it was previously ignored silently). f) The 'blacklist' option in the /etc/shorewall/interfaces and /etc/shorewall/hosts files is now deprecated but will continue to be supported for several releases. A warning will be added at least one release before support is removed. 5) There is now an OUT-BANDWIDTH column in /etc/shorewall/tcinterfaces. The format of this column is: [:[][:[][:[][:[]]]]] These terms are described in tc-tbf(8). Shorewall supplies default values as follows: = 10kb = 200ms The remaining options are defaulted by tc. 6) The IN-BANDWIDTH column in both /etc/shorewall/tcdevices and /etc/shorewall/tcinterfaces now accepts an optional burst parameter. [:] The default is 10kb. A larger can help make the more accurate; often for fast lines, the enforced rate is well below the specified . ---------------------------------------------------------------------------- P R O B L E M S C O R R E C T E D I N 4 . 4 . 1 2 ---------------------------------------------------------------------------- 1) Previously, the Shorewall6-lite version of shorecap was using iptables rather than ip6tables, with the result that many capabilities that are only available in IPv4 were being reported as available. 2) In a number of cases, Shorewall6 generated incorrect rules involving the IPv6 multicast network. The rules specified ff00::/10 where they should have specified ff00::/8. Also, rules instantiated when the firewall was stopped used ff80::/10 rather than fe80::/10 (IPv6 Link Local network). 3) Previously, using a destination port-range with :random produced a fatal compilation error in REDIRECT rules. 4) A number of problems associated with Shorewall-init and Upstart have been corrected. If you use Shorewall-init, then when upgrading to this version, be sure to recompile all firewall scripts before you take interfaces down or reboot. 5) Previously, the Shorewall installer (install.sh) failed to install /usr/share/shorewall/configfiles/Makefile and rather issued the following message: install-file: command not found This caused the Makefile to be omitted from RPMs as well. 6) When 'any' was used in the SOURCE column, a duplicate rule was generated in all "fw2*" ("fw-* if ZONE2ZONE="-"). If 'any' was used in the DEST column, then a duplicate rule appeared in all "*2fw" (*-fw) chains. 7) A port range that omitted the first port number (e.g., ":80") was rejected with the following error: ERROR: Invalid/Unknown tcp port/service (0) : ...... 8) AUTOMAKE=Yes has been broken for some time. It is now working correctly. ---------------------------------------------------------------------------- N E W F E A T U R E S I N 4 . 4 . 1 2 ---------------------------------------------------------------------------- 1) Support has been added for ADD and DEL rules in /etc/shorewall/rules. ADD allows either the SOURCE or DESTINATION IP address to be added to an ipset; DEL deletes an address previously added. 2) Per-ip log rate limiting has been added in the form of the LOGLIMIT option in shorewall.conf. When LOGLIMIT is specified, LOGRATE and LOGBURST are ignored. LOGRATE and LOGBURST are now deprecated. LOGLIMIT value format is [{s|d}:][/][:] If the value starts with 's:' then logging is limited per source IP. If the value starts with 'd:', then logging is limited per destination IP. Otherwise, the overall logging rate is limited. is one of sec, min, hour, day. If is not specified, then a value of 5 is assumed. 3) The sample configurations now include a 'Universal' configuration that will start on any system and protect that system while allowing the system to forward traffic. As part of this change, several additional features were added: - You may now specify "physical=+" in the interfaces file. - A 'COMPLETE' option is added to shorewall.conf and shorewall6.conf. When you set this option to Yes, you are asserting that the configuration is complete so that your set of zones encompasses any hosts that can send or receive traffic to/from/through the firewall. This causes Shorewall to omit the rules that catch packets in which the source or destination IP address is outside of any of your zones. Default is No. It is recommended that this option only be set to Yes if: o You have defined an interface whose effective physical setting is '+' o That interface is assigned to a zone. o You have no CONTINUE policies or rules. 4) 'icmp' is now accepted as a synonym for 'ipv6-icmp' in IPv6 compilations. 5) Shorewall now detects the presence of a recent ipset iptables module and uses its new syntax. This avoids a warning on iptables 1.4.9. This change involves a new capabilities file version so if you use a capabilities file, be sure to regenerate it with 4.4.12 shorewall-lite or shorewall6-lite. 6) Blacklisting can now be done by destination IP address as well as by source address. The /etc/shorewall/blacklist and /etc/shorewall6/blacklist files now have an optional OPTIONS column. Initially, this column can contain either 'from' (the default) or 'to'; the latter causes the address(es) in the ADDRESS/SUBNET column to be interpreted as a DESTINATION address rather than a source address. Note that static blacklisting is still restricted to traffic ARRIVING on an interface that has the 'blacklist' option set. So to block traffic from your local network to an internet host, you must specify 'blacklist' on your internal interface. Similarly, dynamic blacklisting has been enhanced to recognize the 'from' and 'to' keywords. Example: shorewall drop to 1.2.3.4 This command will silently drop connection requests to1.2.3.4. The reciprocal of that command would be: shorewall allow to 1.2.3.4 7) The status command now displays the directory containing the .conf file (shorewall.conf or shorewall6.conf) when the running configuration was compiled. Example: gateway:/etc/shorewall# shorewall status Shorewall-4.4.12-RC1 Status at gateway - Thu Aug 12 19:41:51 PDT 2010 Shorewall is running State:Started (Thu Aug 12 19:41:48 PDT 2010) from /etc/shorewall/ gateway:/etc/shorewall# ---------------------------------------------------------------------------- P R O B L E M S C O R R E C T E D I N 4 . 4 . 1 1 ---------------------------------------------------------------------------- 1) The IPv6 allowBcast action generated an invalid rule. 2) If IPSET= was specified in shorewall.conf, then when an ipset was used in a configuration file entry, the following fatal compilation error occurred: ERROR: ipset names in Shorewall configuration files require Ipset Match in your kernel and iptables : /etc/shorewall/rules (line nn) If you applied the workaround given in the "Known Problems", then you should remove /etc/shorewall/capabilities after installing this fix. 3) The start priority of shorewall-init on Debian and Debian-based distributions was previously too low, making it start too late. 4) The log output from IPv6 logs was almost unreadable due to display of IPv6 addresses in uncompressed format. A similar problem occurred with 'shorewall6 show connections'. This update makes the displays much clearer at the expense of opening the slight possibility of two '::' sequences being incorrectly shown in the same address. 5) The new REQUIRE_INTERFACE was inadvertently omitted from shorewall.conf and shorewall6.conf. It has been added. 6) Under some versions of Perl, a Perl run-time diagnostic was produced when options were omitted from shorewall.conf or shorewall6.conf. 7) If the following options were specified in /etc/shorewall/interfaces for an interface with '-' in the ZONE column, then these options would be ignored if there was an entry in the hosts file for the interface with an explicit or implicit 0.0.0.0/0 (0.0.0.0/0 is implied when the host list begins with '!'). blacklist maclist nosmurfs tcpflags Note: for IPv6, the network is ::/0 rather than 0.0.0.0/0. 8) The generated script was missing a closing quote when REQUIRE_INTERFACE=Yes. 9) Previously, if nets= was specified under Shorewall6, this error would result: ERROR: Invalid IPv6 address (224.0.0.0) : /etc/shorewall6/interfaces (line 16) ---------------------------------------------------------------------------- N E W F E A T U R E S I N 4 . 4 . 1 1 ---------------------------------------------------------------------------- 1) Beginning with this release, Shorewall supports a 'vserver' zone type. This zone type is used with Shorewall running on a Linux-vserver host system and allows you to define zones that represent a set of Linux-vserver hosts. See http://www.shorewall.net/Vserver.html for details. 2) A new FORWARD_CLEAR_MARK option has been added to shorewall.conf and shorewall6.conf. Traditionally, Shorewall has cleared the packet mark in the first rule in the mangle FORWARD chain. This behavior is maintained with the default setting (FORWARD_CLEAR_MARK=Yes). If the new option is set to No, packet marks set in the PREROUTING chain are retained in the FORWARD chains. As part of this change, a new "fwmark route mask" capability has been added. If your version of iproute2 supports this capability, fwmark routing rules may specify a mask to be applied to the mark prior to comparison with the mark value in the rule. The presence of this capability allows Shorewall to relax the restriction that small mark values may not be set in the PREROUTING chain when HIGH_ROUTE_MARKS is in effect. If you take advantage of this capability, be sure that you logically OR mark values in PREROUTING makring rules rather then simply setting them unless you are able to set both the high and low bits in the mark in a single rule. As always when a new capability has been introduced, be sure to regenerate your capabilities file(s) after installing this release. 3) A new column (NET3) has been added to the /etc/shorewall/netmap file. This new column can qualify the INTERFACE column by specifying a SOURCE network (DNAT rule) or DEST network (SNAT rule) associated with the interface. 4) To accomodate systems with more than one version of Perl installed, the shorewall.conf and shorewall6.conf files now support a PERL option. If the program specified by that option does not exist or is not executable, Shorewall (and Shorewall6) fall back to /usr/bin/perl. ---------------------------------------------------------------------------- P R O B L E M S C O R R E C T E D I N 4 . 4 . 1 0 ---------------------------------------------------------------------------- 1) Startup Errors (those that are detected before the state of the system has been altered), were previously not sent to the STARTUP_LOG. 2) A regression of sorts occurred in Shorewall 4.4.9. Previously, a Perl extension script could end with a call to add_rule(). Such a script fails under Shorewall 4.4.9 unless the 'trace' option is specified on the run line. While this issue has been corrected, users are advised to always end their Perl extension scripts with the following line to insure that the script returns a 'true' value: 1; 3) Under rare circumstances involving a complex configuration, OPTIMIZE=13 and OPTIMIZE=15 could cause invalid iptables-restore input to be generated. Sample error message: iptables-restore v1.4.8: Couldn't load target `sys2sys':/usr/local/libexec/xtables/libipt_sys2sys.so: cannot open shared object file: No such file or directory 4) Previously, if the 'optional' option was given to an interface with a wildcard physical name, specific instances of the interface were never considered usable. Example: /etc/shorewall/interfaces: #ZONE INTERFACE BROADCAST OPTIONS net ppp+ - optional /etc/shorewall/providers: #PROVIDER NUMBER MARK DUPLICATE INTERFACE ... XYZTEL 1 - main ppp0 The XYZTEL provider was never usable. This configuration now works correctly. ---------------------------------------------------------------------------- N E W F E A T U R E S I N 4 . 4 . 1 0 ---------------------------------------------------------------------------- 1) Shorewall 4.4.10 includes a new 'Shorewall Init' package. This new package provides two related features: a) It allows the firewall to be closed prior to bringing up network devices. This insures that unwanted connections are not allowed between the time that the network comes up and when the firewall is started. b) It integrates with NetworkManager and distribution ifup/ifdown systems to allow for 'event-driven' startup and shutdown. The two facilities can be enabled separately. When Shorewall-init is first installed, it does nothing until you configure it. The configuration file is /etc/default/shorewall-init on Debian-based systems and /etc/sysconfig/shorewall-init otherwise. There are two settings in the file: PRODUCTS - lists the Shorewall packages that you want to integrate with Shorewall-init. Example: PRODUCTS="shorewall shorewall6" IFUPDOWN When set to 1, enables integration with NetworkManager and the ifup/ifdown scripts. To close your firewall before networking starts: a) in the Shorewall-init configuration file, set PRODUCTS to the firewall products installed on your system. b) be sure that your current firewall script(s) (normally in /var/lib//firewall) is(are) compiled with the 4.4.10 compiler. Shorewall and Shorewall6 users can execute these commands: shorewall compile shorewall6 compile Shorewall-lite and Shorewall6-lite users can execute these commands on the administrative system. shorewall export shorewall6 export That's all that is required. To integrate with NetworkManager and ifup/ifdown, additional steps are required. You probably don't want to enable this feature if you run a link status monitor like swping or LSM. a) In the Shorewall-init configuration file, set IFUPDOWN=1. b) In your Shorewall interfaces file(s), set the 'required' option on any interfaces that must be up in order for the firewall to start. At least one interface must have the 'required' or 'optional' option if you perform the next optional step. If 'required' is specified on an interface with a wildcard name (the physical name ends with '+'), then at least one interface that matches the name must be in a usable state for the firewall to start successfully. c) (Optional) -- If you have specified at least one 'required' or 'optional interface, you can then disable automatic firewall startup at boot time. On Debian-based systems, set startup=0 in /etc/default/. On other systems, use your service startup configuration tool (chkconfig, insserv, ...) to disable startup. The following actions occur when an interface comes up: FIREWALL INTERFACE ACTION STATE ---------------------------------- Any Required start stopped Optional start started - restart The following actions occur when an interface goes down: In the INTERFACE column, '-' indicates neither required nor optional FIREWALL INTERFACE ACTION STATE ---------------------------------- Any Required stop stopped Optional start started - restart For optional interfaces, the /var/lib//.state files are maintained to reflect the state of the interface. Please note that the action is carried out using the current compiled script; the configuration is not recompiled. A new option has been added to shorewall.conf and shorewall6.conf. The REQUIRE_INTERFACE option determines the outcome when an attempt to start/restart/restore/refresh the firewall is made and none of the optional interfaces are available. With REQUIRE_INTERFACE=No (the default), the operation is performed. If REQUIRE_INTERFACE=Yes, then the operation fails and the firewall is placed in the stopped state. This option is suitable for a laptop with both ethernet and wireless interfaces. If either come up, the firewall starts. If neither comes up, the firewall remains in the stopped state. Similarly, if an optional interface goes down and there are no optional interfaces remaining in the up state, then the firewall is stopped. Shorewall-init may be installed on Debian-based systems, SuSE-based systems and RedHat-based systems. On Debian-based systems, during system shutdown the firewall is opened prior to network shutdown (/etc/init.d/shorewall stop performs a 'clear' operation rather than a 'stop'). This is required by Debian standards. You can change this default behavior by setting SAFESTOP=1 in /etc/default/shorewall (/etc/default/shorewall6, ...). 2) All of the CLIs now support the -a option of the 'version' command. Example: gateway:~# shorewall6 version -a 4.4.10-RC1 shorewall: 4.4.10-RC1 shorewall-lite: 4.4.10-RC1 shorewall6-lite: 4.4.10-RC1 shorewall-init: 4.4.10-RC1 gateway:~# ---------------------------------------------------------------------------- P R O B L E M S C O R R E C T E D I N 4 . 4 . 9 ---------------------------------------------------------------------------- 1) Logical interface names in the EXTERNAL column of /etc/shorewall/proxyarp were previously not mapped to their corresponding physical interface names. This could cause 'start' or 'restart' to fail. 2) If find_first_interface_address() was unable to detect an address, then Shorewall 4.4.8 would issue an obscure message (startup_error: command not found) and continue. Now, a meaningful error message is produced and the calling process stops. 3) If LOG_VERBOSITY=0 in shorewall.conf, then when the compiled script was executed, messages such as the following would be issued: /var/lib/shorewall6/.restart: line 65: [: -gt: unary operator expected 4) With optimize 4, if an unnecessary NONAT rule was included in /etc/shorewall/rules (there was no DNAT or REDIRECT rule with the same source zone), then 'shorewall start' and/or 'shorewall restart' could fail with invalid iptables-restore input. 5) The tarball installers now check for the presence of the CLI program (/sbin/shorewall, /sbin/shorewall6, etc) to determine if a fresh install or an upgrade should be performed. Previously, the installers used the presense of the configuration directory (/etc/shorewall, /etc/shorewall6, etc.) which led to incomplete installations where there was an existing configuration directory. 6) The fallback.sh scripts have been removed from Shorewall-lite, Shorewall6, and Shorewall6-lite. These scripts no longer work and should have been removed in 4.4.0. 7) The -lite products previously were inconsistent in how they referred to their startup log. Some references included '-lite' where some did not. This was particularly bad in the case of the Shorewall-lite logrotate file which duplicated the name used by the Shorewall package. This inconsistency could cause logrotate to fail if both packages were installed. 8) Two additional problems with optimize 4 have been corrected. One manifested as invalid iptables-restore input involving the 'tcpre' mangle chain. The other involved wildcard interface names (those ending in '+') and would likely also result in invalid iptables-restore input. 9) Previously, Shorewall would set up infrastructure to handle traffic from the firewall to bport zones. Such infrastructure could never be used. Now, Shorewall avoids setting up these unneeded chains and/or rules. 10) If optimization level 2 and there were no OUTPUT rules and the only effective output policy was $FW->all ACCEPT, then the OUTPUT chain was empty and no packets could be sent. 11) If find_first_interface_address() was called in the params file, a fatal error occured on start/restart. 12) The following valid configuration produced invalid iptables-restore input with optimization level 4. /etc/shorewall/interfaces: #ZONE INTERFACE BROADCAST OPTIONS vpn tun+ - /etc/shorewall/masq: #INTERFACE SOURCE ADDRESS PROTO PORT tun0 192.168.1.0/24 Use of tunN in the nat and netmap files also produced invalid iptables-restore input. 2) '/sbin/shorewall version -a' now shows the versions of all installed Shorewall packages. ---------------------------------------------------------------------------- N E W F E A T U R E S I N 4 . 4 . 9 ---------------------------------------------------------------------------- 1) The compiler now auto-detects bridges for the purpose of setting the 'routeback' option. Auto-detection is disabled when compiling for export (-e option); note that -e is implicit in the 'load' and 'reload' commands. 2) When 'trace' is specified on a command that involves the compiler (e.g., shorewall trace check), the compiler now creates a trace to standard output. Trace entries are of three types: Input --- begin with IN===>. Input read from configuration files. Comments have been stripped, continuation lines combined and shell variables expanded. Output --- begin with GS----->. Text written to the generated script. Netfilter -- begin with NF-(x)->. Updates to the compiler's chain table, where 'x' is one of the following: N - Create a chain. A - Append a rule to a chain. R - Replace a rule in a chain. I - Inserted a rule into a chain. T - Shell source text appended/inserted into a chain -- converted into rules at run-time. D - Deleted Rule from a chain; note that this causes the following rules to be renumbered. X - Deleted a chain P - Change a built-in chains policy. Chains in the filter table are created with a DROP policy. All other builtin chains have policy ACCEPT. ! Followed by one or more of the following to indicate that the operation is not allowed on the chain. O - Optimize D - Delete M - Move rules Netfilter trace records indicate the table and chain being changed. If the change involves a particular rule, then the rule number is also included. Example (append the first rule to the filter FORWARD chain): NF-(A)-> filter:FORWARD:1 ... If the trace record involves the chain itself, then no rule number is present. Example (Delete the mangle tcpost chain): NF-(X)-> mangle:tcpost 3) Thanks to Vincent Smeets, there is now an IPv6 mDNS macro. 4) Optimize 8 has been added. This optimization level eliminates duplicate chains. So to set all possible optimizations, specify OPTIMIZE=15. 5) The command-line tools now support 'show log ' where is a regular expression to search for in the LOGFILE. The command searches the current LOGFILE for Netfilter messages matching the supplied regex. 6) There are some instances where a bridge with no IP address is configured. Prior to Shorewall 4.4.9, this required the following: /etc/shorewall/interfaces: #ZONE INTERFACE BROADCAST OPTIONS dummy br0 - routeback /etc/shorewall/policy: #SOURCE DEST POLICY dummy all DROP all dummy DROP Beginning in this release, a single entry will suffice: /etc/shorewall/interfaces: #ZONE INTERFACE BROADCAST OPTIONS - br0 - bridge 7) The generated ruleset now uses conntrack match for state matching, if it is available. 8) In /etc/shorewall/routestopped, the 'routeback' option is assumed if the interface has 'routeback' specified (either explicitly or detected). 9) Apple Macs running OS X may now be used as a Shorewall administrative system. Simply install using the tarball installer. ---------------------------------------------------------------------------- P R O B L E M S C O R R E C T E D I N 4 . 4 . 9 ---------------------------------------------------------------------------- 1) A CONTINUE rule specifying a log level would cause the compiler to generate an incorrect rule sequence. The packet would be logged but the CONTINUE action would not occur. 2) If multiple entries were present in /etc/shorewall/tcdevices and globally unique class numbers were not explicitly specified in /etc/shorewall/tcclasses, then 'shorewall start' would fail with a diagnostic such as: Setting up Traffic Control... RTNETLINK answers: File exists ERROR: Command "tc qdisc add dev eth1 parent 2:2 handle 2: sfq quantum 1500 limit 127 perturb 10" Failed Processing /etc/shorewall/stop ... 3) Previously, when a low per-IP rate limit (such as 1/hour) was specified, the effective enforced rate was much higher (approximately 6/min). The Shorewall compiler now configures the hashlimit table idle timeout based on the rate units (min, hour, ...) so that the rate is more accurately enforced. As part of this change, a unique hash table name is assigned to each per-IP rate limiting rule that does not specify a table name in the rule. The assigned names are of the form 'shorewallN' where N is an integer. Previously, all such rules shared a single 'shorewall' table which lead to unexpected results. 4) All versions of Shorewall-perl mishandle per-IP rate limiting in REDIRECT, DNAT and ACCEPT+ rules. The effective rate and burst are 1/2 of the values given in the rule. 5) Detection of the 'Old hashlimit match' capability was broken in /sbin/shorewall, /sbin/shorewall-lite and in the IPv4 version of shorecap. 6) On older distributions such as RHEL5 and derivatives, Shorewall would fail to start if a TYPE was specified in /etc/shorewall/tcinterfaces and LOAD_HELPERS_ONLY had been specified in /etc/shorewall/shorewall.conf. 7) The Debian init scripts are modified to include $remote_fs in the Required-start and Required-stop specifications. 8) Previously, when a supported command failed, the Debian Shorewall init script would still return a success (zero) exit status. It now returns a failure status (1) when the command fails. 9) Previously, if a queue number was specified in an NFQUEUE policy (e.g., NFQUEUE(0)), invalid iptables-restore input would be generated. 10) Previously, with optimization 4, users of ipsec on older releases such as RHEL5 and CentOS, could encounter an error similar to this one: Running /sbin/iptables-restore... iptables-restore v1.3.5: Unknown arg `out' Error occurred at line: 93 Try `iptables-restore -h' or 'iptables-restore --help' for more information. ERROR: iptables-restore Failed. Input is in /var/lib/shorewall/.iptables-restore-input 11) Previously, with optimization 4, the 'blacklst' chain could be optimized away. If the blacklist file was then changed and a 'shorewall refresh' executed, those new changes would not be included in the active ruleset. 12) In 4.4.7, it was documented that setting the 'bridge' option in an interfaces file entry also set 'routeback'. That feature was incomplete with the result that 'routeback' still needed to be specified. ---------------------------------------------------------------------------- N E W F E A T U R E S I N 4 . 4 . 8 ---------------------------------------------------------------------------- 1) To avoid variable name collisions, a number of shell variable names that Shorewall uses and that are in all capital letters have been changed. The following variables are now safe to use in your /etc/shorewall/params file and in your extension scripts: DEBUG ECHO_E ECHO_N EXPORT FAST HOSTNAME IPT_OPTIONS NOROUTES PREVIEW PRODUCT PROFILE PURGE RECOVERING RESTOREPATH RING_BELL STOPPING TEST TIMESTAMP USE_VERBOSITY VERBOSE VERBOSE_OFFSET VERSION See Migration Issue 14 above for additional information. 2) The Shorewall and Shorewall6 installers now accept a '-s' (sparse) option. That option causes only shorewall.conf to be installed in /etc/shorewall/. 3) An OpenPGP HTTP Keyserver Protocol (HKP) macro (macro.HKP) has been contributed. 4) In an attempt to help those who don't read the documentation, the compiler now flags apparent use of '-' as a port range separator with an error message. Example: /etc/shorewall/rules #ACTION SOURCE DEST PROTO DEST # PORT(S) ACCEPT net fw tcp 21-22 Resulting error message ERROR: The separator for a port range is ':', not '-' (21-22) : /etc/shorewall/rules (line 3) 5) Support has been added for UDPLITE (proto 136) in that DEST PORT(S) and SOURCE PORT(S) may now be specified for that protocol. 6) If a runtime error occurs during a 'start' or 'restart' operation but a saved configuration is successfully restored, a subsequent 'status' command now gives the detailed status as 'Restored from ' rather than 'Started'; is the saved script used to restore the configuration. ---------------------------------------------------------------------------- P R O B L E M S C O R R E C T E D I N 4 . 4 . 7 ---------------------------------------------------------------------------- 1) The tcinterfaces and tcpri files are now installed by the installer and are included in the rpm. 2) An invalid octal number (e.g., 080) appearing in a port list resulted in a perl error message. As part of this fix, both hex and octal numbers are now accepted for protocol and port numbers. 3) In 4.4.6, if a system: a) Had mangle table support. b) Had a FORWARD chain in the mangle table. c) Did not have MARK Target support. then 'shorewall start' would fail. 4) Previously, the 'nosmurfs' option was ignored in IPv6 compilations. As part of this fix, 'nosmurfs' handling when SMURF_LOG_LEVEL is specified has been improved for both IPv4 and IPv6. 5) Previously, specifying a TYPE in /etc/shorewall/tcinterfaces would cause start/restart to fail on systems lacking 'flow' classifier support. In Shorewall 4.4.7, we detect the ability of the 'tc' utility to support that classifier. There are two caveats: - 'tc' may support 'flow' but the kernel does not. In that case, start/restart will still fail. - If you use a capabilities file, you will need to regenerate the file using shorewall-lite 4.4.7 in order for 'flow' to be accurately detected. If you do not regenerate the file, the compiler will use other hints to try to determine if 'flow' is available. ---------------------------------------------------------------------------- N E W F E A T U R E S I N 4 . 4 . 7 ---------------------------------------------------------------------------- 1) The OPTIMIZE option value is now a bit-map with each bit controlling a separate set of optimizations. - The low-order bit (value 1) controls optimizations available in earlier releases. We refer to this optimization as "optimization 1". - The next bit (value 2) suppresses superfluous ACCEPT rules in a policy chain that implements an ACCEPT policy. Any ACCEPT rules that immediately preceed the final blanket ACCEPT rule in the chain are now omitted. We refer to this optimization as "optimization 2". - The next bit (value 4 or "optimization 4") enables the following additional optimizations: a) Empty chains are optimized away. b) Chains with one rule are optimized away. c) If a built-in chain has a single rule that branches to a second chain, then the rules from the second chain are moved to the built-in chain and the target chain is omitted. d) Chains with no references are deleted. e) Accounting chains are subject to optimization if the new OPTIMIZE_ACCOUNTING option is set to 'Yes' (default is 'No'). f) If a chain ends with an unconditional branch to a second chain (other than to 'reject'), then the branch is deleted from the first chain and the rules from the second chain are appended to it. The following chains are exempted from optimization 4: action chains (user-created). accounting chains (unless OPTIMIZE_ACCOUNTING=Yes) dynamic forwardUPnP logdrop logreject rules chains (those of the form zonea2zoneb or zonea-zoneb). UPnP (nat table). To enable all possible optimizations, set OPTIMIZE to 7 (1 + 2 + 4). 2) Shorewall now combines identical logging chains. Previously, a separate chain was created for each logging rule. 3) Beginning with Shorewall 4.4.7, accounting can be disabled by setting ACCOUNTING=No in shorewall.conf. This allows you to keep a set of accounting rules configured in /etc/shorewall/accounting and to then enable and disable them by simply toggling the setting of ACCOUNTING. Similarly, dynamic blacklisting can be disabled by setting DYNAMIC_BLACKLIST=No. This saves a jump rule in the INPUT and FORWARD filter chains.. 4) Shorewall can now automatically assign mark values to providers in cases where 'track' is specified (or TRACK_PROVIDERS=Yes) but packet marking is otherwise not used for directing connections to a particular provider. Simply specify '-' in the MARK column and Shorewall will automatically assign a mark value. 5) Support for TPROXY has been added. See http://www.shorewall.net/Shorewall_Squid_Usage.html#TPROXY. 6) Traditionally, Shorewall has loaded all modules that could possibly be needed twice; once in the compiler, and once when the generated script is initialized. The latter can be a time-consuming process on slow hardware. Beginning with 4.4.7, there is a LOAD_HELPERS_ONLY option in shorewall.conf. For existing users, LOAD_HELPERS_ONLY=No is the default. For new users that employ the sample configurations, LOAD_HELPERS_ONLY=Yes will be the default. That setting causes only a small subset of modules to be loaded; it is assumed that the remaining modules will be autoloaded. Additionally, capability detection in the compiler is deferred until each capability is actually used. As a consequence, no modules are autoloaded unnecessarily. Modules loaded when LOAD_HELPERS_ONLY=Yes are the protocol helpers. These cannot be autoloaded. In addition, the nf_conntrack_sip module is loaded with sip_direct_media=0. This setting is slightly less secure than sip_direct_media=1, but it solves many VOIP problems that users routinely encounter. ---------------------------------------------------------------------------- P R O B L E M S C O R R E C T E D I N 4 . 4 . 6 ---------------------------------------------------------------------------- 1) A 'feature' of xtables-addons when applied to Debian Lenny causes extra /31 networks to appear for nethash sets in the output of "ipset -L" and "ipset -S". A hack has been added to prevent these from being saved when Shorewall is saving IPSETS during 'stop'. As part of this change, the generated script is more careful about verifying the existence of the correct ipset utility before using it to save the contents of the sets. 2) The mDNS macro previously did not include IGMP (protocol 2) and it did not specify the mDNS multicast address (224.0.0.251). These omissions have been corrected. ---------------------------------------------------------------------------- N E W F E A T U R E S I N 4 . 4 . 6 ---------------------------------------------------------------------------- 1) In kernel 2.6.31, the handling of the rp_filter interface option was changed incompatibly. Previously, the effective value was determined by the setting of net.ipv4.config.dev.rp_filter logically ANDed with the setting of net.ipv4.config.all.rp_filter. Beginning with kernel 2.6.31, the value is the arithmetic MAX of those two values. Given that Shorewall sets net.ipv4.config.all.rp_filter to 1 if there are any interfaces specifying 'routefilter', specifying 'routefilter' on any interface has the effect of setting the option on all interfaces. To allow Shorewall to handle this issue, a number of changes were necessary: a) There is no way to safely determine if a kernel supports the new semantics or the old so the Shorewall compiler uses the kernel version reported by uname. b) This means that the kernel version is now recorded in the capabilities file. So if you use capabilities files, you need to regenerate the files with Shorewall[-lite] 4.4.6 or later. c) If the capabilities file does not contain a kernel version, the compiler assumes version 2.6.30 (the old rp_filter behavior). d) The ROUTE_FILTER option in shorewall.conf now accepts the following values: 0 or No - Shorewall sets net.ipv4.config.all.rp_filter to 0. 1 or Yes - Shorewall sets net.ipv4.config.all.rp_filter to 1. 2 - Shorewall sets net.ipv4.config.all.rp_filter to 2. Keep - Shorewall does not change the setting of net.ipv4.config.all.rp_filter if the kernel version is 2.6.31 or later. The default remains Keep. e) The 'routefilter' interface option can have values 0,1 or 2. If 'routefilter' is specified without a value, the value 1 is assumed. 2) SAVE_IPSETS=Yes has been resurrected but in a different form. With this setting, the contents of your ipsets are saved during 'shorewall stop' and 'shorewall save' and they are restored during 'shorewall start' and 'shorewall restore'. Note that the contents may only be restored during 'restore' if the firewall is currently in the stopped state and there are no ipsets currently in use. In particular, when 'restore' is being executed to recover from a failed start/restart, the contents of the ipsets are not changed. When SAVE_IPSETS=Yes, you may not include ipsets in your /etc/shorewall/routestopped configuration. 3) IPv6 addresses following a colon (":") may either be surrounded by <..> or by the more standard [..]. 4) A DHCPfwd macro has been added that allows unicast DHCP traffic to be forwarded through the firewall. Courtesy of Tuomo Soini. 5) Shorewall (/sbin/shorewall) now supports a 'show macro' command: shorewall show macro Example: shorewall show macro LDAP The command displays the contents of the macro. file. 6) You may now preview the generated ruleset by using the '-r' option to the 'check' command (e.g., "shorewall check -r"). The output is a shell script fragment, similar to the way it appears in the generated script. 7) It is now possible to enable a simplified traffic shaping facility by setting TC_ENABLED=Simple in shorewall.conf. See http://www.shorewall.net/simple_traffic_shaping.html for details. 8) Previously, when TC_EXPERT=No, packets arriving through 'tracked' provider interfaces were unconditionally passed to the PREROUTING tcrules. This was done so that tcrules could reset the packet mark to zero, thus allowing the packet to be routed using the 'main' routing table. Using the main table allowed dynamic routes (such as those added for VPNs) to be effective. The route_rules file was created to provide a better alternative to clearing the packet mark. As a consequence, passing these packets to PREROUTING complicates things without providing any real benefit. Beginning with this release, when TRACK_PROVIDERS=Yes and TC_EXPERT=No, packets arriving through 'tracked' interfaces will not be passed to the PREROUTING rules. Since TRACK_PROVIDERS was just introduced in 4.4.3, this change should be transparent to most, if not all, users. ---------------------------------------------------------------------------- P R O B L E M S C O R R E C T E D I N 4 . 4 . 5 ---------------------------------------------------------------------------- 1) The change which removed the 15 port limitation on /etc/shorewall/routestopped was incomplete. The result was that if more than 15 ports were listed, an error was generated. 2) If any interfaces had the 'bridge' option specified, compilation failed with the error: Undefined subroutine &Shorewall::Rules::match_source_interface called at /usr/share/shorewall/Shorewall/Rules.pm line 2319. 3) The compiler now flags port number 0 as an error in all contexts. Previously, port 0 was allowed with the result that invalid iptables-restore input could be generated in some cases. 4) The 'show policies' command now works in Shorewall6 and Shorewall6-lite. 5) Traffic shaping modules from /lib/modules//net/sched/ are now correctly loaded. Previously, that directory was not searched. Additionally, Shorewall6 now tries to load the cls_flow module; previously, only Shorewall attempts to load that module. 6) The Shorewall6-lite shorecap program was previously including the IPv4 base library rather than the IPv6 version. Also, Shorewall6 capability detection was determing the availablity of the mangle capability before it had determined if ip6tables was installed. 7) The setting of MODULE_SUFFIX was previously ignored except when compiling for export. 8) Detection of the Enhanced Reject capability in the compiler was broken for IPv4 compilations. 9) The 'reload -c' command would ignore the setting of DONT_LOAD in shorewall.conf. The 'reload' command without '-c' worked as expected. ---------------------------------------------------------------------------- N E W F E A T U R E S I N 4 . 4 . 5 ---------------------------------------------------------------------------- 1) Shorewall now allows DNAT rules that change only the destination port. Example: DNAT loc net::456 udp 234 That rule will modify the destination port in UDP packets received from the 'loc' zone from 456 to 234. Note that if the destination is the firewall itself, then the destination port will be rewritten but that no ACCEPT rule from the loc zone to the $FW zone will have been created to handle the request. So such rules should probably exclude the firewall's IP addresses in the ORIGINAL DEST column. 2) Systems that do not log Netfilter messages locally can now set LOGFILE=/dev/null in shorewall.conf. 3) The 'shorewall show connections' and 'shorewall dump' commands now display the current number of connections and the max supported connections. Example: shorewall show connections Shorewall 4.5.0 Connections (62 out of 65536) at gateway - Sat ... In that case, there were 62 current connections out of a maximum number supported of 65536. ---------------------------------------------------------------------------- P R O B L E M S C O R R E C T E D I N 4 . 4 . 4 ---------------------------------------------------------------------------- 1) In some simple one-interface configurations, the following Perl run-time error messages were issued: Generating Rule Matrix... Use of uninitialized value in concatenation (.) or string at /usr/share/shorewall/Shorewall/Chains.pm line 649. Use of uninitialized value in concatenation (.) or string at /usr/share/shorewall/Shorewall/Chains.pm line 649. Creating iptables-restore input... 2) The Shorewall operations log (specified by STARTUP_LOG) is now secured 0600. 3) Previously, the compiler generated an incorrect test for interface availability in the generated code for adding route rules. The result was that the rules were always added, regardless of the state of the provider's interface. Now, the rules are only added when the interface is available. 4) When TC_WIDE_MARKS=Yes and class numbers are not explicitly specified in /etc/shorewall/tcclasses, duplicate class numbers result. A typical error message is: ERROR: Command "tc class add dev eth3 parent 1:1 classid 1:1 htb rate 1024kbit ceil 100000kbit prio 1 quantum 1500" Failed Note that the class ID of the class being added is a duplicate of the parent's class ID. Also, when TC_WIDE_MARKS=Yes, values > 255 in the MARK column of /etc/shorewall/tcclasses were rejected. ---------------------------------------------------------------------------- N E W F E A T U R E S I N 4 . 4 . 4 ---------------------------------------------------------------------------- 1) The Shorewall packages now include a logrotate configuration file. 2) The limit of 15 entries in a port list has been relaxed in /etc/shorewall/routestopped. 3) The following seemingly valid configuration produces a fatal error reporting "Duplicate interface name (p+)" /etc/shorewall/zones: #ZONE TYPE fw firewall world ipv4 z1:world bport4 z2:world bport4 /etc/shorewall/interfaces: #ZONE INTERFACE BROADCAST OPTIONS world br0 - bridge world br1 - bridge z1 br0:p+ z2 br1:p+ This error occurs because the Shorewall implementation requires that each bridge port must have a unique name. To work around this problem, a new 'physical' interface option has been created. The above configuration may be defined using the following in /etc/shorewall/interfaces: #ZONE INTERFACE BROADCAST OPTIONS world br0 - bridge world br1 - bridge z1 br0:x+ - physical=p+ z2 br1:y+ - physical=p+ In this configuration, 'x+' is the logical name for ports p+ on bridge br0 while 'y+' is the logical name for ports p+ on bridge br1. If you need to refer to a particular port on br1 (for example p1023), you write it as y1023; Shorewall will translate that name to p1023 when needed. It is allowed to have a physical name ending in '+' with a logical name that does not end with '+'. The reverse is not allowed; if the logical name ends in '+' then the physical name must also end in '+'. This feature is not restricted to bridge ports. Beginning with this release, the interface name in the INTERFACE column can be considered a logical name for the interface, and the actual interface name is specified using the 'physical' option. If no 'physical' option is present, then the physical name is assumed to be the same as the logical name. As before, the logical interface name is used throughout the rest of the configuration to refer to the interface. 4) Previously, Shorewall has used the character '2' to form the name of chains involving zones and/or the word 'all' (e.g., fw2net, all2all). When zones names are given numeric suffixes, these generated names are hard to read (e.g., foo1232bar). To make these names clearer, a ZONE2ZONE option has been added. ZONE2ZONE has a default value of "2" but can also be given the value "-" (e.g., ZONE2ZONE="-") which causes Shorewall to separate the two parts of the name with a hyphen (e.g., foo123-bar). 5) Only one instance of the following warning is now generated; previously, one instance of a similar warning was generated for each COMMENT encountered. COMMENTs ignored -- require comment support in iptables/Netfilter 6) The shorewall and shorewall6 utilities now support a 'show policies' command. Once Shorewall or Shorewall6 has been restarted using a script generated by this version, the 'show policies' command will list each pair of zones and give the applicable policy. If the policy is enforced in a chain, the name of the chain is given. Example: net => loc DROP using chain net2all Note that implicit intrazone ACCEPT policies are not displayed for zones associated with a single network where that network doesn't specify 'routeback'. 7) The 'show' and 'dump' commands now support an '-l' option which causes chain displays to include the rule number of each rule. (Type 'iptables -h' and look for '--line-number') ---------------------------------------------------------------------------- P R O B L E M S C O R R E C T E D I N 4 . 4 . 3 ---------------------------------------------------------------------------- 1. Previously, if 'routeback' was specified in /etc/shorewall/routestopped: a) 'shorewall check' produced an internal error b) The 'routeback' option didn't work 2) If an alias IP address was added and RETAIN_ALIASES=No in shorewall.conf, then a compiler internal error resulted. 3) Previously, the generated script would try to detect the values for all run-time variables (such as IP addresses), regardless of what command was being executed. Now, this information is only detected when it is needed. 4) Nested zones where the parent zone was defined by a wildcard interface (name ends with +) in /etc/shorewall/interfaces did not work correctly in some cases. 5) IPv4 addresses embedded in IPv6 (e.g., ::192.168.1.5) were incorrectly reported as invalid. 6) Under certain circumstances, optional providers were not detected as being usable. Additionally, the messages issued when an optional provider was not usable were confusing; the message intended to be issued when the provider shared an interface ("WARNING: Gateway is not reachable -- Provider () not Added") was being issued when the provider did not share an interface. Similarly, the message intended to be issued when the provider did not share an interface ("WARNING: Interface is not usable -- Provider () not Added") was being issued when the provider did share an interface. ---------------------------------------------------------------------------- N E W F E A T U R E S I N 4 . 4 . 3 ---------------------------------------------------------------------------- 1) On Debian systems, a default installation will now set INITLOG=/dev/null in /etc/default/shorewall. In all configurations, the default values for the log variables are changed to: STARTUP_LOG=/var/log/shorewall-init.log LOG_VERBOSITY=2 The effect is much the same as the old defaults, with the exception that: a) Start, stop, etc. commands issued through /sbin/shorewall will be logged. b) Logging will occur at maximum verbosity. c) Log entries will be date/time stamped. On non-Debian systems, new installs will now log all Shorewall commands to /var/log/shorewall-init.log. 2) A new TRACK_PROVIDERS option has been added in shorewall.conf. The value of this option becomes the default for the 'track' provider option in /etc/shorewall/providers. 3) A new 'limit' option has been added to /etc/shorewall/tcclasses. This option specifies the number of packets that are allowed to be queued within the class. Packets exceeding this limit are dropped. The default value is 127 which is the value that earlier versions of Shorewall used. The option is ignored with a warning if the 'pfifo' option has been specified. ---------------------------------------------------------------------------- P R O B L E M S C O R R E C T E D I N 4 . 4 . 2 ---------------------------------------------------------------------------- 1) Detection of Persistent SNAT was broken in the rules compiler. 2) Initialization of the compiler's chain table was occurring before shorewall.conf had been read and before the capabilities had been determined. This could lead to incorrect rules and Perl runtime errors. 3) The 'shorewall check' command previously did not detect errors in /etc/shorewall/routestopped. 4) In earlier versions, if a file with the same name as a built-in action were present in the CONFIG_PATH, then the compiler would process that file like it was an extension script. The compiler now ignores the presence of such files. 5) Several configuration issues which previously produced an error or warning are now handled differently. a) MAPOLDACTIONS=Yes and MAPOLDACTIONS= in shorewall.conf are now handled as they were by the old shell-based compiler. That is, they cause pre-3.0 built-in actions to be mapped automatically to the corresponding macro invocation. b) SAVE_IPSETS=Yes no longer produces a fatal error -- it is now a warning. c) DYNAMIC_ZONES=Yes no longer produces a fatal error -- it is now a warning. d) RFC1918_STRICT=Yes no longer produces a fatal error -- it is now a warning. 6) Previously, it was not possible to specify an IP address range in the ADDRESS column of /etc/shorewall/masq. Thanks go to Jessee Shrieve for the patch. 7) The 'wait4ifup' script included for Debian compatibility now runs correctly with no PATH. 8) The new per-IP LIMIT feature now works with ancient iptables releases (e.g., 1.3.5 as found on RHEL 5). This change required testing for an additional capability which means that those who use a capabilities file should regenerate that file after installing 4.4.2. 9) One unintended difference between Shorewall-shell and Shorewall-perl was that Shorewall-perl did not support the MARK column in action bodies. This has been corrected. ---------------------------------------------------------------------------- N E W F E A T U R E S I N 4 . 4 . 2 ---------------------------------------------------------------------------- 1) Prior to this release, line continuation has taken precedence over #-style comments. This prevented us from doing the following: ACCEPT net:206.124.146.176,\ #Gateway 206.124.146.177,\ #Mail 206.124.146.178\ #Server ... Now, unless a line ends with '\', any trailing comment is stripped off (including any white-space preceding the '#'). Then if the line ends with '\', it is treated as a continuation line as normal. 2) Three new columns have been added to FORMAT-2 macro bodies. MARK CONNLIMIT TIME These three columns correspond to the similar columns in /etc/shorewall/rules and must be empty in macros invoked from an action. 3) Accounting chains may now have extension scripts. Simply place your Perl script in the file /etc/shorewall/ and when the accounting chain named is created, your script will be invoked. As usual, the variable $chainref will contain a reference to the chain's table entry. ---------------------------------------------------------------------------- P R O B L E M S C O R R E C T E D I N 4 . 4 . 1 ---------------------------------------------------------------------------- 1) If ULOG was specified as the LOG LEVEL in the all->all policy, the rules at the end of the INPUT and OUTPUT chains would still use the LOG target rather than ULOG. 2) Using CONTINUE policies with a nested IPSEC zone was still broken in some cases. 3) The setting of IP_FORWARDING has been change to Off in the one-interface sample configuration since forwarding is typically not required with only a single interface. 4) If MULTICAST=Yes in shorewall.conf, multicast traffic was incorrectly exempted from ACCEPT policies. 5) Previously, the definition of a zone that specified "nets=" in /etc/shorewall/interfaces could not be extended by entries in /etc/shorewall/hosts. 6) Previously, "nets=" could be specified in a multi-zone interface definition ("-" in the ZONES column) in /etc/shorewall/zones. This now raises a fatal compilation error. 7) MULTICAST=Yes generates an incorrect rule that limits its effectiveness to a small part of the multicast address space. 8) Checking for zone membership has been tighened up. Previously, a zone could contain :0.0.0.0/0 along with other hosts; now, if the zone has :0.0.0.0/0 (even with exclusions), then it may have no additional members in /etc/shorewall/hosts. ---------------------------------------------------------------------------- N E W F E A T U R E S I N 4 . 4 . 1 ---------------------------------------------------------------------------- 1) To replace the SAME keyword in /etc/shorewall/masq, support has been added for 'persistent' SNAT. Persistent SNAT is required when an address range is specified in the ADDRESS column and when you want a client to always receive the same source/destination IP pair. It replaces SAME: which was removed in Shorewall 4.4.0. To specify persistence, follow the address range with ":persistent". Example: #INTERFACE SOURCE ADDRESS eth0 0.0.0.0/0 206.124.146.177-206.124.146.179:persistent This feature requires Persistent SNAT support in your kernel and iptables. If you use a capabilities file, you will need to create a new one as a result of this feature. WARNING: Linux kernels beginning with 2.6.29 include persistent SNAT support. If your iptables supports persistent SNAT but your kernel does not, there is no way for Shorewall to determine that persistent SNAT isn't going to work. The kernel SNAT code blindly accepts all SNAT flags without verifying them and returns them to iptables when asked. 2) A 'clean' target has been added to the Makefiles. It removes backup files (*~ and .*~). 3) The meaning of 'full' has been redefined when used in the context of a traffic shaping sub-class. Previously, 'full' always meant the OUT-BANDWIDTH of the device. In the case of a sub-class, however, that definition is awkward to use because the sub-class is limited by the parent class. Beginning with this release, 'full' in a sub-class definition refers to the specified rate defined for the parent class. So 'full' used in the RATE column refers to the parent class's RATE; when used in the CEIL column, 'full' refers to the parent class's CEIL. As part of this change, the compiler now issues a warning if the sum of the top-level classes' RATEs exceeds the OUT-BANDWIDTH of the device. Similarly, a warning is issued if the sum of the RATEs of a class's sub-classes exceeds the rate of the CLASS. 4) When 'nets=' or 'nets=(,,...) is specified in /etc/shorewall/interfaces, multicast traffic will now be sent to the zone along with limited broadcasts. 5) A flaw in the parsing logic for the zones file allowed most zone types containing the character string 'ip' to be accepted as a synonym for 'ipv4' (or ipv6 if compiling an IPv6 configuration). ---------------------------------------------------------------------------- N E W F E A T U R E S I N 4 . 4 . 0 ---------------------------------------------------------------------------- 1) The Shorewall packaging has been completely revamped in Shorewall 4.4. The new packages are: - Shorewall. Includes the former Shorewall-common and Shorewall-perl packages. Includes everything needed to create an IPv4 firewall. Shorewall-shell is no longer available. - Shorewall6. Requires Shorewall. Adds the components necessary to create an IPv6 firewall. - Shorewall-lite May be installed on a firewall system to run IPv4 firewall scripts generated by Shorewall. - Shorewall6-lite May be installed on a firewall system to run IPv6 firewall scripts generated by Shorewall6. 2) The interfaces file supports a new 'nets=' option. This option allows you to restrict a zone's definition to particular networks through an interface without having to use the hosts file. Example interfaces file: #ZONE INTERFACE BROADCAST OPTIONS loc eth3 detect dhcp,logmartians=1,routefilter=1,nets=172.20.1.0/24 dmz eth4 detect logmartians=1,routefilter=1,nets=206.124.146.177 net eth0 detect dhcp,blacklist,tcpflags,optional,routefilter=0,nets=(!172.20.0.0/24,206.124.146.177) net eth2 detect dhcp,blacklist,tcpflags,optional,upnp,routefilter=0,nets=(!172.20.0.0/24,206.124.146.177) loc tun+ detect nets=172.20.0.0/24 #LAST LINE -- ADD YOUR ENTRIES BEFORE THIS ONE -- DO NOT REMOVE Note that when more than one network address is listed, the list must be enclosed in parentheses. Notice also that exclusion may be used. The first entry in the above interfaces file is equivalent to the following: interfaces: #ZONE INTERFACE BROADCAST OPTIONS - eth0 detect dhcp,logmartians=1,routefilter=1 hosts: #ZONE HOST(S) OPTIONS loc $INT_IF:192.20.1.0/24 broadcast Note that the 'broadcast' option is automatically assumed and need not be explicitly specified. 3) Some websites run applications that require multiple connections from a client browser. Where multiple 'balanced' providers are configured, this can lead to problems when some of the connections are routed through one provider and some through another. To work around this issue, the SAME target has been added to /etc/shorewall/tcrules. SAME may be used in the PREROUTING and OUTPUT chains. When used in PREROUTING, it causes matching connections from an individual local system to all use the same provider. For example: SAME:P 192.168.1.0/24 - tcp 80,443 If a host in 192.168.1.0/24 attempts a connection on TCP port 80 or 443 and it has sent a packet on either of those ports in the last five minutes then the new connection will use the same provider as the connection over which that last packet was sent. When used in the OUTPUT chain, it causes all matching connections to an individual remote system to use the same provider. For example: SAME $FW - tcp 80,443 If the firewall attempts a connection on TCP port 80 or 443 and it has sent a packet on either of those ports in the last five minutes to the same remote system then the new connection will use the same provider as the connection over which that last packet was sent. Important note: SAME only works with providers that have the 'track' option specified in /etc/shorewall/providers. 4) The file /var/lib/shorewall/.restore has been renamed to /var/lib/shorewall/firewall. A similar change has been made in Shorewall6. When a successful start or restart is completed, the script that executed the command copies itself to /var/lib/shorewall[6]/firewall. As always, /var/lib/shorewall[6] is the default directory which may be overridden using the /etc/shorewall[6]/vardir file. 5) Dynamic zone support is once again available for IPv4. This support is built on top of ipsets so you must have the xtables-addons installed on the firewall system. See http://www.shorewall.net/Dynamic.html for information about this feature and for instructions for installing xtables-addons on your firewall. Dynamic zones are available when Shorewall-lite is used as well. You define a zone as having dynamic content in one of two ways: - By specifying nets=dynamic in the OPTIONS column of an entry for the zone in /etc/shorewall/interfaces; or - By specifying :dynamic in the HOST(S) column of an entry for the zone in /etc/shorewall/hosts. When there are any dynamic zones present in your configuration, Shorewall (Shorewall-lite) will: a) Execute the following commands during 'shorewall start' or 'shorewall-lite start'. ipset -U :all: :all: ipset -U :all: :default: ipset -F ipset -X ipset -R < ${VARDIR}/ipsets.save where $VARDIR normally contains /var/lib/shorewall (/var/lib/shorewall-lite) but may be modified by /etc/shorewall/vardir (/etc/shorewall-lite/vardir). b) During 'start', 'restart' and 'restore' processing, Shorewall will attempt to create an ipset named _ for each zone/interface pair that has been specified as dynamic. The type of ipset created is 'iphash' so that only individual IPv4 addresses may be added to the set. c) Execute the following commands during 'shorewall stop' or 'shorewall-lite stop': if ipset -S > ${VARDIR}/ipsets.tmp; then mv -f ${VARDIR}/ipsets.tmp ${VARDIR}/ipsets.save fi The 'shorewall add' and 'shorewall delete' commands are supported with their original syntax: add [:] ... delete [:] ... In addition, the 'show dynamic' command is added that lists the dynamic content of a zone. show dynamic These commands are supported by shorewall-lite as well. 6) The generated program now attempts to detect all dynamic information when it first starts. Dynamic information includes IP addresses, default gateways, networks routed through an interface, etc. If any of those steps fail, an error message is generated and the state of the firewall is not changed. 7) To improve the readability of configuration files, Shorewall now allows leading white space in continuation lines when the continued line ends in ":" or ",". Example (/etc/shorewall/rules): #ACTION SOURCE DEST PROTO DEST # PORT(S) ACCEPT net:\ 206.124.146.177,\ 206.124.146.178,\ 206.124.146.180\ dmz tcp 873 The leading white space on the lines that contain just an IP address is ignored so the SOURCE column effectively contains "net:206.124.146.177,206.124.147.178,206.124.146.180". 8) The generated script now uses iptables[6]-restore to instantiate the Netfilter ruleset during processing of the 'stop' command. As a consequence, the 'critical' option in /etc/shorewall/route_stopped is no longer needed and will result in a warning. 9) A new AUTOMAKE option has been added to shorewall.conf and shorewall6.conf. When set to 'Yes', this option causes new behavior during processing of the 'start' and 'restart' commands; if no files in /etc/shorewall/ (/etc/shorewall6) have changed since the last 'start' or 'restart', then the compilation step is skipped and the script used during the last 'start' or 'restart' is used to start/restart the firewall. Note that if a is specified in the start/restart command (e.g., "shorewall restart /etc/shorewall.new") then the setting of AUTOMAKE is ignored. Note that the 'make' utility must be installed on the firewall system in order for AUTOMAKE=Yes to work correctly. 10) The 'compile' command now allows you to omit the . When you do that, the defaults to /var/lib/shorewall/firewall (/var/lib/shorewall6/firewall) unless you have overridden VARDIR using /etc/shorewall/vardir (/etc/shorewall6/vardir). When combined with AUTOMAKE=Yes, it allows the following: gateway:~ # shorewall compile Compiling... Shorewall configuration compiled to /root/shorewall/firewall gateway:~ # ... gateway:~ # shorewall restart Restarting Shorewall.... done. gateway:~ # In other words, you can compile the current configuration then install it at a later time. 11) Thanks to I. Buijs, it is now possible to rate-limit connections by source IP or destination IP. The LIMIT:BURST column in /etc/shorewall/policy (/etc/shorewall6/policy) and the RATE LIMIT column /etc/shorewall/rules (/etc/shorewall6/rules) have been extended as follows: [{s|d}:[[]:]]/{sec|min}[:] When s: is specified, the rate is per source IP address. When d: is specified, the rate is per destination IP address. The specifies the name of a hash table -- you get to choose the name. If you don't specify a name, the name 'shorewall' is assumed. Rules with the same name have their connection counts aggregated and the individual rates are applied to the aggregate. Example: ACCEPT net fw tcp 22 - - s:ssh:3/min This will limit SSH connections from net->fw to 3 per minute. ACCEPT net fw tcp 25 - - s:mail:3/min ACCEPT net fw tcp 587 - - s:mail:3/min Since the same hash table name is used in both rules, the above is equivalent to this single rule: ACCEPT net fw tcp 25,587 - - s:mail:3/min 12) Rules that specify a log level with a target other than LOG or NFLOG are now implemented through a separate chain. While this may increase the processing cost slightly for packets that match these rules, it is expected to reduce the overall cost of such rules because each packet that doesn't match the rules only has to be processed once per rule rather than twice. Example: /etc/shorewall/rules: REJECT:info loc net tcp 25 This previously generated these two rules (long rules folded): -A loc2net -p 6 --dport 25 -j LOG --log-level 6 --log-prefix "Shorewall:loc2net:reject:" -A loc2net -p 6 --dport 25 -j reject It now generates these rules: :log0 - [0:0] ... -A loc2net -p 6 --dport 25 -g log0 ... -A log0 -j LOG --log-level 6 --log-prefix "Shorewall:loc2net:REJECT:" -A log0 -j reject Notice that now there is only a single rule generated in the 'loc2net' chain where before there were two. Packets for other than TCP port 25 had to be processed by both rules. Notice also that the new LOG rule reflects the original action ("REJECT") rather than what Shorewall maps that to ("reject"). 13) Shorewall6 has now been tested on kernel 2.6.24 (Ubuntu Hardy) and hence will now start successfully when running on that kernel. 14) Three new options (IP, TC and IPSET) have been added to shorewall.conf and shorewall6.conf. These options specify the name of the executable for the 'ip', 'tc' and 'ipset' utilities respectively. If not specified, the default values are: IP=ip TC=tc IPSET=ipset In other words, the utilities will be located via the current PATH setting. 15) There has been a desire in the user community to limit traffic by IP address using Shorewall traffic shaping. Heretofore, that has required a very inefficient process: a) Define a tcclass for each internal host (two, if shaping both in and out). b) Define a tcrule for each host to mark to classify the packets accordingly. Beginning with Shorewall 4.4, this process is made easier IF YOU ARE WILLING TO INSTALL xtables-addons. The feature requires IPMARK support in iptables[6] and your kernel. That support is available in xtables-addons. Instructions for installing xtables-addons may be found at http://www.shorewall.net/Dynamic.html#xtables-addons. The new facility has two components: a) A new IPMARK MARKing command in /etc/shorewall/tcrules. b) A new 'occurs' OPTION in /etc/shorewall/tcclasses. The facility is currently only available with IPv4. In a sense, the IPMARK target is more like an IPCLASSIFY target in that the mark value is later interpreted as a class ID. A packet mark is 32 bits wide; so is a class ID. The class occupies the high-order 16 bits and the class occupies the low-order 16 bits. So the class ID 1:4ff (remember that class IDs are always in hex) is equivalent to a mark value of 0x104ff. Remember that Shorewall uses the interface number as the number where the first interface in tcdevices has number 1, the second has number 2, and so on. The IPMARK target assigns a mark to each matching packet based on the either the source or destination IP address. By default, it assigns a mark value equal to the low-order 8 bits of the source address. The syntax is as follows: IPMARK[([{src|dst}][,[][,[][,[]]]])] Default values are: src = 0xFF = 0x00 = 0 'src' and 'dst' specify whether the mark is to be based on the source or destination address respectively. The selected address is first shifted right by , then LANDed with and then LORed with . The argument is intended to be used primarily with IPv6 addresses. Example: IPMARK(src,0xff,0x10100) Destination IP address is 192.168.4.3 = 0xc0a80403 0xc0a80403 >> 0 = 0xc0a80403 0xc0a80403 LAND 0xFF = 0x03 0x03 LOR 0x10100 = 0x10103 So the mark value is 0x10103 which corresponds to class id 1:103. It is important to realize that, while class IDs are composed of a and a value, the set of values must be unique. You must keep this in mind when deciding how to map IP addresses to class IDs. For example, suppose that your internal network is 192.168.1.0/29 (host IP addresses 192.168.1.1 - 192.168.1.6). Your first notion might be to use IPMARK(src,0xFF,0x10000) so as to produce class IDs 1:1 through 1:6. But 1:1 is the class ID of the base HTB class on interface 1. So you might chose instead to use IPMARK(src,0xFF,0x10100) as shown in the example above so as to avoid minor class 1. The 'occurs' option in /etc/shorewall/tcclasses causes the class definition to be replicated many times. The synax is: occurs= When 'occurs' is used: a) The associated device may not have the 'classify' option. b) The class may not be the default class. c) The class may not have any 'tos=' options (including 'tcp-ack'). d) The class should not specify a MARK value. Any MARK value given is ignored with a warning. The 'RATE' and 'CEIL' parameters apply to each instance of the class. So the total RATE represented by an entry with 'occurs' will be the listed RATE multiplied by the 'occurs' number. Example: /etc/shorewall/tcdevices: #INTERFACE IN-BANDWIDTH OUT-BANDWIDTH eth0 100mbit 100mbit /etc/shorewall/tcclasses: #DEVICE MARK RATE CEIL PRIORITY OPTIONS eth0:101 - 1kbit 230kbit 4 occurs=6 The above defines 6 classes with class IDs 0x101-0x106. Each class has a guaranteed rate of 1kbit/second and a ceiling of 230kbit. /etc/shorewall/tcrules: #MARK SOURCE DEST IPMARK(src,0xff,0x10100):F 192.168.1.0/29 eth0 This change also altered the way in which Shorewall generates a class number when none is given. - Prior to this change, the class number was constructed by concatinating the mark value with the either '1' or '10'. '10' was used when there were more than 10 devices defined in /etc/shorewall/tcdevices. - Beginning with this change, a new method is added; class numbers are assigned sequentially beginning with 2. The WIDE_TC_MARKS option in shorewall.conf selects which construction to use. WIDE_TC_MARKS=No (the default) produces pre-4.4 behavior. WIDE_TC_MARKS=Yes produces the new behavior. In addition to determining the method of constructing class Ids, WIDE_TC_MARKS=Yes provides for larger mark values for traffic shaping. Traffic shaping marks may have values up to 16383 (0x3fff) with WIDE_TC_MARKS=Yes. This means that when both WIDE_TC_MARKS=Yes and HIGH_ROUTE_MARKS=Yes, routing marks (/etc/shorewall/providers MARK column) must be >= 65536 (0x10000) and must be a multiple of 65536 (0x1000, 0x20000, 0x30000, ...). 16) In the 'shorewall compile' and 'shorewall6 compile' commands, the filename '-' now causes the compiled script to be written to Standard Out. As a side effect, the effective VERBOSITY is set to -1 (silent). Examples: shorewall compile -- - # Compile the configuration in # /etc/shorewall and send the # output to STDOUT shorewall compile . - # Compile the configuration in the # current working directory # and send the output to STDOUT 17) Supplying an interface name in the SOURCE column of /etc/shorewall/masq is now deprecated. Entering the name of an interface there will result in a compile-time warning (see the Migration Considerations above). 18) Shorewall now supports nested HTB traffic shaping classes. The nested classes within a class can borrow from their parent class in the same way as the first level classes can borrow from the root class. To use nested classes, you must explicitly number your classes. That does not imply that you must use the 'classify' option. Example: /etc/shorewall/tcdevices #INTERFACE IN-BANDWITH OUT-BANDWIDTH OPTIONS eth2 - 100mbps classify /etc/shorewall/tcclasses #INTERFACE MARK RATE CEIL PRIORITY OPTIONS 1:10 - full/2 full 1 1:100 - 16mbit 20mbit 2 1:100:101 - 8mbit 20mbit 3 default 1:100:102 - 8mbit 20mbit 3 /etc/shorewall/tcrules #MARK SOURCE DEST 1:102 0.0.0.0/0 eth2:172.20.1.107 1:10 206.124.146.177 eth2 1:10 172.20.1.254 eth2 The above controls download for internal interface eth2. The external interface has a download rate of 20mbit so we guarantee that to class 1:100. 1:100 has two subclasses, each of which is guaranteed half of their parent's bandwidth. Local traffic (that coming from the firewall and from the DMZ server) is placed in the effectively unrestricted class 1:10. The default class is guaranteed half of the download capacity and my work system (172.20.1.107) is guarandeed the other half. 19) Support for the "Hierarchical Fair Service Curve" (HFSC) queuing discipline has been added. HFSC is claimed to be superior to the "Hierarchical Token Bucket" queuing discipline where realtime traffic such as VOIP is being used. An excellent overview of HFSC on Linux may be found at http://linux-ip.net/articles/hfsc.en/. To use HFSC, several changes need to be made to your traffic shaping configuration: - To use HFSC on an interface rather than HTB, specify the 'hfsc' option in the OPTIONS column in the interfaces's entry in /etc/shorewall/tcdevices. - Modify the RATE colum for each 'leaf' class (class with no parent class specified) defined for the interface. When using HFSC, the RATE column may specify 1, 2 or 3 pieces of information separated by colons (":"). 1. The Guaranteed bandwidth (as always). 2. The Maximum delay (DMAX) that the first queued packet in the class should experience. The delay is expressed in milliseconds and may be followed by 'ms' (e.g., 10ms. Note that there may be no white space between the number and 'ms'). 3. The maximum transmission unit (UMAX) for this class of traffic. If not specified, the MTU of the interface is used. The length is specified in bytes and may be followed by 'b' (e.g., 800b. Note that there may be no white space between the number and 'b'). DMAX should be specified for each leaf class. The Shorewall compiler will issue a warning if DMAX is omitted. Example: full/2:10ms:1500b Guaranteed bandwidth is 1/2 of the devices OUT-BANDWIDTH. Maximum delay is 10ms. Maximum packet size is 1500 bytes. 20) Optional TOS and LENGTH fields have been added to the tcfilters file. The TOS field may contain any of the following: tos-minimize-delay tos-maximuze-throughput tos-maximize-reliability tos-minimize-cost tos-normal-service Hex-number Hex-number/Hex-number The hex numbers must have exactly two digits. The LENGTH value must be a numeric power of two between 32 and 8192 inclusive. Packets with a total length that is strictly less that the specified value will match the rule. 21) Support for 'norfc1918' has been removed. See the Migration Considerations above. 22) A 'upnpclient' option has been added to /etc/shorewall/interfaces. This option is intended for laptop users who always run Shorewall on their system yet need to run UPnP-enabled client apps such as Transmission (BitTorrent client). The option causes Shorewall to detect the default gateway through the interface and to accept UDP packets from that gateway. Note that, like all aspects of UPnP, this is a security hole so use this option at your own risk. 23) 'iptrace' and 'noiptrace' commands have been added to both /sbin/shorewall and /sbin/shorewall6. These are low-level debugging commands that cause iptables/ip6tables TRACE log messages to be generated. See 'man iptables' and 'man ip6tables' for details. The syntax for the commands is: iptrace noiptrace iptrace starts the trace; noiptrace turns it off. The match expression must be an expression that is legal in both the raw table OUTPUT and PREROUTING chains. Examaple: To trace all packets destinted for IP address 206.124.146.176: shorewall iptrace -d 206.124.146.176 To turn that trace off: shorewall noiptrace -d 206.124.146.176 24) A USER/GROUP column has been added to /etc/shorewall/masq. The column works similarly to USER/GROUP columns in other Shorewall configuration files. Only locally-generated traffic is matched. 25) A new extension script, 'lib.private' has been added. This file is intended to include declarations of shell functions that will be called by the other run-time extension scripts. 26) Paul Gear has contributed the following macros: macro.Webcache (originally named macro.DG) macro.IPPbrd macro.NTPbi macro.RIPbi macro.mDNS 27) The default value of DISABLE_IPV6 has been changed from 'Yes' to 'No' in all sample shorewall.conf files. Shorewall6 should be installed to restrict IPv6 traffic. As part of this change, the ip6tables program in the directory specified by the IPTABLES setting will be used to disable IPv6. If the iptables utility is discovered using the PATH setting, then ip6tables in the same directory as the discovered iptables will be used. 28) A 'flow=' option has been added to the /etc/shorewall/tcclasses OPTIONS column. Shorewall attaches an SFQ queuing discipline to each leaf HTB and HFSC class. SFQ ensures that each flow gets equal access to the interface. The default definition of a flow corresponds roughly to a Netfilter connection. So if one internal system is running BitTorrent, for example, it can have lots of 'flows' and can thus take up a larger share of the bandwidth than a system having only a single active connection. The flow classifier (module cls_flow) works around this by letting you define what a 'flow' is. The clasifier must be used carefully or it can block off all traffic on an interface! The flow option can be specified for an HTB or HFSC leaf class (one that has no sub-classes). We recommend that you use the following: Shaping internet-bound traffic: flow=nfct-src Shaping traffic bound for your local net: flow=dst These will cause a 'flow' to consists of the traffic to/from each internal system. When more than one key is give, they must be enclosed in parenthesis and separated by commas. To see a list of the possible flow keys, run this command: tc filter add flow help Those that begin with "nfct-" are Netfilter connection tracking fields. As shown above, we recommend flow=nfct-src; that means that we want to use the source IP address before SNAT as the key. Note: Shorewall cannot determine ahead of time if the flow classifier is available in your kernel (especially if it was built into the kernel as opposed to being loaded as a module). Consequently, you should check ahead of time to ensure that both your kernel and 'tc' utility support the feature. You can test the 'tc' utility by typing (as root): tc filter add flow help If flow is supported, you will see: Usage: ... flow ... [mapping mode]: map key KEY [ OPS ] ... [hashing mode]: hash keys KEY-LIST ... ... If flow is not supported, you will see: Unknown filter "flow", hence option "help" is unparsable If your kernel supports module autoloading, just type (as root): modprobe cls_flow If 'flow' is supported, no output is produced; otherwise, you will see: FATAL: Module cls_flow not found. If your kernel is not modularized or does not support module autoloading, look at your kernel configuration (either /proc/config.gz or the .config file in /lib/modules//build/ If 'flow' is supported, you will see: NET_CLS_FLOW=m or NET_CLS_FLOW=y For modularized kernels, Shorewall will attempt to load /lib/modules//net/sched/cls_flow.ko by default.