shorewall_code/Shorewall/releasenotes.txt

Shorewall 3.3.3
	  	 
 Note to users upgrading from Shorewall 3.0 or 3.3	 
  	 
    Most problems associated with upgrades come from two causes: 	 
	  	 
    - The user didn't read and follow the migration considerations in these 	 
      release notes. 	 
	  	 
    - The user mis-handled the /etc/shorewall/shorewall.conf file during 	 
      upgrade. Shorewall is designed to allow the default behavior of 	 
      the product to evolve over time. To make this possible, the design 	 
      assumes that you will not replace your current shorewall.conf file 	 
      during upgrades. If you feel absolutely compelled to have the latest 	 
      comments and options in your shorewall.conf then you must proceed 	 
      carefully. 	 
	  	 
    While you are at it, if you have a file named /etc/shorewall/rfc1918 then 	 
    please check that file. If it has addresses listed that are NOT in one of 	 
    these three ranges, then please rename the file to 	 
    /etc/shorewall/rfc1918.old. 	 
  	 
         10.0.0.0 - 10.255.255.255 	 
         172.16.0.0 - 172.31.255.255 	 
         192.168.0.0 - 192.168.255.255 	 
  	 
    If you have a file named /etc/shorewall/modules, please remove 	 
    it. The default modules file is now located in /usr/share/shorewall/ 	 
    (see the "Migration Considerations" below). 	 
  	 
    Please see the "Migration Considerations" below for additional upgrade 	 
    information. 	 
  	 
Problems Corrected in 3.3.3

1)  Previously, the 'provider' portion of the packet mark was not being
    cleared after routing for traffic that originates on the firewall
    itself.

Other changes in 3.3.3

1)  For users whose kernel and iptables have Extended MARK Target
    support, it is now possible to logically AND or OR a value into the
    current packet mark by preceding the mark value (and optional mask)
    with an ampersand ("&") or vertical bar ("|") respectively.

    Example: To logically OR the value 4 into the mark value for
    packets from 192.168.1.1:

    #MARK   SOURCE
    |4	    192.168.1.1

2)  Previously, zone names were restricted to five characters in
    length. That length derives from the --log-prefix in Netfilter log
    messages which must be 29 bytes or less in length. With the
    standard Shorewall LOGFORMAT, 11 characters are left for the
    chain name; since many chain names are of the form
    <zone1>2<zone2>, we have a maximum zone name length of 5.

    Beginning with this release, the maximum length of a zone name is
    dependent on the LOGFORMAT (the maximum length may never be less
    than 5 but it may be greater than 5). For example, setting
    LOGFORMAT="FW:%s:%s:" will allow zone names of up to 8 characters.

    As part of this change, /sbin/shorewall[-lite] no longer uses the
    LOGFORMAT to select Shorewall messages from log files. Instead, it
    uses the regular expression /IN=.* OUT=/ which will match any
    netfilter-generated log message.

3)  Netfilter provides support for attaching comments to Netfilter 
    rules. Comments can be up to 255 bytes in length and are 
    visible using the "shorewall show <chain>", "shorewall show nat",
    "shorewall show mangle" and "shorewall dump" commands. Comments are
    delimited by '/* ... */" in the output.

    Beginning with Shorewall 3.3.3, you may place COMMENT lines in the
    /etc/shorewall/rules, /etc/shorewall/tcrules, /etc/shorewall/nat
    and /etc/shorewall/masq files. The remainder of the line is treated
    as a comment and it will be attached as a Netfilter comment to the
    rule(s) generated by the next entry in the file.

    If you do not have Comment support in your iptables/kernel (see the
    output of "shorewall[-lite] show capabilities") then COMMENTS are
    ignored with this warning:

     COMMENT ignored --  requires comment support in iptables/Netfilter

    Example from my rules file:

	    #SOURCE      SOURCE     DEST       PROTO DEST PORT(S)
	    
	    COMMENT Stop Microsoft Crap

	    REJECT       loc        net        tcp   137,445
	    REJECT       loc        net        udp   137:139

    The output of "shorewall show loc2net" includes (folded):

    0     0 reject     tcp  --  *      *       0.0.0.0/0
	  0.0.0.0/0    multiport dports 137,445 /* Stop Microsoft crap */
    0     0 reject     udp  --  *      *       0.0.0.0/0
	  0.0.0.0/0    udp dpts:137:139

Migration Considerations:

1)  Shorewall supports the notion of "default actions". A default
    action defines a set of rules that are applied before a policy is
    enforced. Default actions accomplish two goals:

    a) Relieve log congestion. Default actions typically include rules
       to silently drop or reject traffic that would otherwise be logged
       when the policy is enforced.

    b) Ensure correct operation. Default actions can also avoid common
       pitfalls like dropping connection requests on port TCP port
       113. If these connections are dropped (rather than rejected)
       then you may encounter problems connecting to internet services
       that utilize the AUTH protocol of client authentication.

    In prior Shorewall versions, default actions (action.Drop and
    action.Reject) were defined for DROP and REJECT policies in
    /usr/share/shorewall/actions.std. These could be overridden in
    /etc/shorewall/actions.

    This approach has two drawbacks:

    a) All DROP policies must use the same default action and all
       REJECT policies must use the same default action.

    b) Now that we have modularized action processing (see the New
       Features section below), we need a way to define default rules
       for a policy that does not involve actions.

    If you have not overridden the defaults using entries in
    /etc/shorewall/actions then you need make no changes to migrate to
    Shorewall version 3.3. Otherwise, please see item 3) in the New
    Features below.

2)  The 'Limit' action is now a builtin. If you have 'Limit' listed in
    /etc/shorewall/actions, remove the entry. Also remove the files
    /etc/shorewall/action.Limit and/or /etc/shorewall/Limit if you have
    them.

New Features:

1)  In order to accomodate small embedded applications, Shorewall 3.3
    is now modularized. In addition to the base files, there are
    loadable "libraries" that may be included or omitted from an
    embedded system as required.

    Loadable Shorewall libraries reside in /usr/share/shorewall/ and
    have names that begin with "lib.". The following libraries are
    included in Shorewall 3.3:

    - lib.accounting. Must be available if you include entries in
      /etc/shorewall/accounting.

    - lib.actions. Must be available if you do not specify 
      USE_ACTIONS=No in /etc/shorewall/shorewall.conf.

    - lib.dynamiczones. Must be available if you specify
      DYNAMIC_ZONES=Yes in shorewall.conf.

    - lib.maclist. Must be available if you specify the 'maclist'
      option in /etc/shorewall/interfaces or /etc/shorewall/hosts.

    - lib.nat. Must be available if you have entries in
      /etc/shorewall/masq, /etc/shorewall/nat or /etc/shorewall/netmap.

    - lib.providers. Must be available if you have entries in
      /etc/shorewall/providers.

    - lib.proxyarp. Must be available if you have entries in
      /etc/shorewall/proxyarp or if you specify the 'proxyarp' option
      in /etc/shorewall/interfaces.

    - lib.tc. Must be available if you have entries in
      /etc/shorewall/tcdevices and /etc/shorewall/tcclasses.

    - lib.tcrules. Must be available if you have entries in
      /etc/shorewall/tcrules.

    - lib.tunnels. Must be available if you have entries in
      /etc/shorewall/tunnels.

    Embedded applications can further decrease the size of the Shorewall
    footprint by:

    - Omitting the macro files.
    - Only including the 'modules' file appropriate for the kernel in
      use.
    - Omitting all unused extension scripts.
    - Stripping the comments (except for copyright) from the various
      files.

2)  As hinted in the previous bullet, there is a new USE_ACTIONS option
    in /etc/shorewall/shorewall.conf. Shorewall actions can be very
    powerful but they also require a lot of code to implement. Embedded
    applications can omit that code by setting
    USE_ACTIONS=No. Shorewall will ignore all action-related files
    including /usr/share/shorewall/actions.std and
    /etc/shorewall/actions. Builtin actions will still be available for
    use in rules and macros.

    The 'Limit' action has been converted to a builtin so that Limit is
    available even when USE_ACTIONS=No.

    See the next item for more information.

3)  Prior to Shorewall 3.3, default actions were specified in
    /usr/share/shorewall/actions.std or in /etc/shorewall/actions.

    This approach has two drawbacks:

    a) All DROP policies must use the same default action and all
       REJECT policies must use the same default action.

    b) Now that we have modularized action processing (see the New
       Features section below), we need a way to define default rules
       for a policy that does not involve actions.

    The solution is two-fold:

    - Four new options have been added to the
      /etc/shorewall/shorewall.conf file that allow specifying the
       default action for DROP, REJECT, ACCEPT and QUEUE.

       The options are DROP_DEFAULT, REJECT_DEFAULT, ACCEPT_DEFAULT and
       QUEUE_DEFAULT.

       DROP_DEFAULT describes the rules to be applied before a
       connection request is dropped by a DROP policy; REJECT_DEFAULT
       describes the rules to be applied if a connection request is
       rejected by a REJECT policy. The other two are similar for
       ACCEPT and QUEUE policies.

       The value assigned to these may be:

       	a) The name of an action. 
	b) The name of a macro
	c) 'None' or 'none'

       The default values are:

	DROP_DEFAULT="Drop"
	REJECT_DEFAULT="Reject"
	ACCEPT_DEFAULT=none
	QUEUE_DEFAULT=none

       If USE_ACTIONS=Yes, then these values refer to action.Drop and
       action.Reject respectively. If USE_ACTIONS=No, then these values
       refer to macro.Drop and macro.Reject.

       If you set the value of either option to "None" then no default
       action will be used and the default action or macro must be
       specified in /etc/shorewall/policy

    - The POLICY column in /etc/shorewall/policy has been extended.

       In /etc/shorewall/policy, when the POLICY is DROP, REJECT,
       ACCEPT or QUEUE then the policy may be followed by ":" and one
       of the following:
			
	a) The word "None" or "none". This causes any default
	   action defined in /etc/shorewall/shorewall.conf
	   to be omitted for this policy.
	b) The name of an action (requires that USE_ACTIONS=Yes
	   in shorewall.conf). That action will be invoked 
	   before the policy is enforced.
	c) The name of a macro. The rules in that macro will
	   be applied before the policy is enforced. This
	   does not require USE_ACTIONS=Yes.

    Example:

	#SOURCE		DEST		POLICY		LOG
	#						LEVEL
	loc		net		ACCEPT
	net		all		DROP:MyDrop	info
	#
	# THE FOLLOWING POLICY MUST BE LAST
	#
	all		all		REJECT:MyReject	info

4)  For users whose kernel and iptables have Extended MARK Target
    support, it is now possible to logically AND or OR a value into the
    current packet mark by preceding the mark value (and optional mask)
    with an ampersand ("&") or vertical bar ("|") respectively.

    Example: To logically OR the value 4 into the mark value for
    packets from 192.168.1.1:

    #MARK   SOURCE
    |4	    192.168.1.1

5)  Previously, zone names were restricted to five characters in
    length. That length derives from the --log-prefix in Netfilter log
    messages which must be 29 bytes or less in length. With the
    standard Shorewall LOGFORMAT, that leaves 11 characters for the
    chain name; given that many chain names are of the form
    <zone1>2<zone2>, that gives a maximum zone name length of 11.

    Beginning with this release, the maximum length of a zone name is
    dependent on the LOGFORMAT (the maximum length may never be less
    than 5 but it may be greater than 5). For example, setting
    LOGFORMAT="FW:%s:%s:" will allow zone names of up to 8 characters.