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shorewall_code/Shorewall/releasenotes.txt
Tom Eastep 7eddb8310a Clean up rate limiting fixes (documentation) 
Signed-off-by: Tom Eastep <teastep@shorewall.net>
2010-02-18 07:09:22 -08:00

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Shorewall 4.4.7 Patch Release 5.
----------------------------------------------------------------------------
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.
----------------------------------------------------------------------------
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 <child>:<parent>,... 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 <interface>:0.0.0.0/0 along with other hosts;
now, if the zone has <interface>: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).
----------------------------------------------------------------------------
P R O B L E M S C O R R E C T E D I N 4 . 4 . 7 . 5
----------------------------------------------------------------------------
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 prior versions of Shorewall-perl mishandle per-IP rate limiting
in REDIRECT and DNAT rules. The effective rate and burst are 1/2 of
the values given in the rule. This problem has been corrected so
that the specified rate is now the effective rate.
----------------------------------------------------------------------------
P R O B L E M S C O R R E C T E D I N 4 . 4 . 7 . 4
----------------------------------------------------------------------------
1) The Debian init scripts are modified to include $remote_fs in the
Required-start and Required-stop specifications.
----------------------------------------------------------------------------
P R O B L E M S C O R R E C T E D I N 4 . 4 . 7 . 3
----------------------------------------------------------------------------
1) On older distributions such as RHEL5 and derivatives, when
LOAD_HELPERS_ONLY=Yes, Shorewall would fail to start if a TYPE was
specified in /etc/shorewall/tcinterfaces.
----------------------------------------------------------------------------
P R O B L E M S C O R R E C T E D I N 4 . 4 . 7 . 2
----------------------------------------------------------------------------
1) Detection of the 'Old hashlimit match' capability was broken in
/sbin/shorewall, /sbin/shorewall-lite and in the IPv4 version of
shorecap.
2) On older distributions such as RHEL5 and derivatives, when
LOAD_HELPERS_ONLY=No, Shorewall would fail to start if a TYPE was
specified in /etc/shorewall/tcinterfaces.
----------------------------------------------------------------------------
P R O B L E M S C O R R E C T E D I N 4 . 4 . 7 . 1
----------------------------------------------------------------------------
1) All versions of Shorewall-perl mishandle per-IP rate limiting in
REDIRECT and DNAT rules. The effective rate and burst are 1/2 of
the values given in the rule.
----------------------------------------------------------------------------
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.
----------------------------------------------------------------------------
K N O W N P R O B L E M S R E M A I N I N G
----------------------------------------------------------------------------
None.
----------------------------------------------------------------------------
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 <macro>
Example:
shorewall show macro LDAP
The command displays the contents of the macro.<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/<version>/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 <gateway> is not
reachable -- Provider <name> (<number>) 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 <interface> is not usable --
Provider <name> (<number>) 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/<chain> and when the
accounting chain named <chain> 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 <interface>:0.0.0.0/0 along with other hosts;
now, if the zone has <interface>: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=<network>' or 'nets=(<net1>,<net2>,...) 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 <interface>: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 <zone>_<interface>
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 <interface>[:<host-list>] ... <zone>
delete <interface>[:<host-list>] ... <zone>
In addition, the 'show dynamic' command is added that lists the dynamic
content of a zone.
show dynamic <zone>
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 <directory> 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 <pathname>. When
you do that, the <pathname> 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}:[[<name>]:]]<rate>/{sec|min}[:<burst>]
When s: is specified, the rate is per source IP address.
When d: is specified, the rate is per destination IP address.
The <name> 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 shorwall6.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 <major> class occupies
the high-order 16 bits and the <minor> 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 <major> number where the
first interface in tcdevices has <major> number 1, the second has
<major> 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}][,[<mask1>][,[<mask2>][,[<shift>]]]])]
Default values are:
src
<mask1> = 0xFF
<mask2> = 0x00
<shift> = 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 <shift>, then
LANDed with <mask1> and then LORed with <mask2>. The <shift>
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
<major> and a <minor> value, the set of <minor> 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=<number>
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/shoreall/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 <iptables/ip6tables match expression>
noiptrace <iptables/ip6tables match expression>
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=<keys>' 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/<kernel-version>/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/<kernel-version>/net/sched/cls_flow.ko by default.
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