Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover, and with no Back-Cover Texts. A copy of the license is included in the section entitled <quote><ulinkurl="copyright.htm"type="">GNU Free Documentation License</ulink></quote>.
It is important that you read all of the sections on this page where the version number mentioned in the section title is later than what you are currently running.
</para>
<para>
In the descriptions that follows, the term <emphasis>group</emphasis> refers to a particular network or subnetwork (which may be <literal>0.0.0.0/0</literal> or it may be a host address) accessed through a particular interface.
</para>
<para>
Examples:
</para>
<simplelistcolumns="1"type="vert">
<member>
<literal>eth0:0.0.0.0/0</literal>
</member>
<member>
<literal>eth2:192.168.1.0/24</literal>
</member>
<member>
<literal>eth3:192.0.2.123</literal>
</member>
</simplelist>
<para>
You can use the <commandmoreinfo="none">shorewall check</command> command to see the groups associated with each of your zones.
The meaning of <varname>ROUTE_FILTER=Yes</varname> has changed. Previously this setting was documented as causing route filtering to occur on all network interfaces; this didn't work. Beginning with this release, <varname>ROUTE_FILTER=Yes</varname> causes route filtering to occur on all interfaces brought up while Shorewall is running. This means that it may be appropriate to set <varname>ROUTE_FILTER=Yes</varname> and use the routefilter option in <filenameclass="directory">/etc/shorewall/</filename><filename>interfaces</filename> entries.
The <varname>NAT_ENABLED</varname>, <varname>MANGLE_ENABLED</varname> and <varname>MULTIPORT</varname> options have been removed from <filename>shorewall.conf</filename>. These capabilities are now automatically detected by Shorewall.
</para>
</listitem>
<listitem>
<para>
An undocumented feature previously allowed entries in the host file as follows:
<synopsis>
zone eth1:192.168.1.0/24,eth2:192.168.2.0/24
</synopsis>
This capability was never documented and has been removed in 1.4.6 to allow entries of the following format:
If you are upgrading from 1.4.3 and have set the <varname>LOGMARKER</varname> variable in <filenameclass="directory">/etc/shorewall/</filename><filename>shorewall.conf</filename>, then you must set the new <varname>LOGFORMAT</varname> variable appropriately and remove your setting of <varname>LOGMARKER</varname>.
If you have zone names that are 5 characters long, you may experience problems starting Shorewall because the <option>--log-prefix</option> in a logging rule is too long. Upgrade to Version 1.4.4a to fix this problem.
There are some cases where you may want to handle traffic from a particular group to itself. While I personally think that such a setups are ridiculous, there are two cases covered in this documentation where it can occur:
<itemizedlist>
<listitem>
<para>
<ulinkurl="FAQ.htm#faq2">In FAQ #2</ulink>
</para>
</listitem>
<listitem>
<para>
<ulinkurl="Shorewall_Squid_Usage.html">When running <application>Squid</application> as a transparent proxy in your local zone.</ulink>
</para>
</listitem>
</itemizedlist>
If you have either of these cases, you will want to review the current documentation and change your configuration accordingly.
Beginning with Version 1.4.1, traffic between groups in the same zone is accepted by default. Previously, traffic from a zone to itself was treated just like any other traffic; any matching rules were applied followed by enforcement of the appropriate policy. With 1.4.1 and later versions, unless you have explicit rules for traffic from Z to Z or you have an explicit Z to Z policy (where "Z" is some zone) then traffic between the groups in zone Z will be accepted. If you do have one or more explicit rules for Z to Z or if you have an explicit Z to Z policy then the behavior is as it was in prior versions.
</para>
<orderedlistnumeration="arabic">
<listitem>
<para>
If you have a Z Z ACCEPT policy for a zone to allow traffic between two interfaces to the same zone, that policy can be removed and traffic between the interfaces will traverse fewer rules than previously.
</para>
</listitem>
<listitem>
<para>
If you have a Z Z DROP or Z Z REJECT policy or you have Z->Z rules then your configuration should not require any change.
</para>
</listitem>
<listitem>
<para>
If you are currently relying on a implicit policy (one that has "all" in either the SOURCE or DESTINATION column) to prevent traffic between two interfaces to a zone Z and you have no rules for Z->Z then you should add an explicit DROP or REJECT policy for Z to Z.
</para>
</listitem>
</orderedlist>
</listitem>
<listitem>
<para>
Sometimes, you want two separate zones on one interface but you don't want Shorewall to set up any infrastructure to handle traffic between them.
Here, zone z1 is nested in zone z2 and the firewall is not going to be involved in any traffic between these two zones. Beginning with Shorewall 1.4.1, you can prevent Shorewall from setting up any infrastructure to handle traffic between z1 and z2 by using the new NONE policy:
<example>
<title>The contents of <filename>policy</filename></title>
Note that NONE policies are generally used in pairs unless there is asymetric routing where only the traffic on one direction flows through the firewall and you are using a NONE polciy in the other direction.
In Version 1.4.1, Shorewall will never create rules to deal with traffic from a given group back to itself. The <varname>multi</varname> interface option is no longer available so if you want to route traffic between two subnetworks on the same interface then I recommend that you upgrade to Version 1.4.2 and use the <varname>routeback</varname> interface or host option.
Shorewall >=1.4.0 requires the <command>iproute</command> package ('<literal>ip</literal>' utility).
</para>
</important>
<note>
<para>
Unfortunately, some distributions call this package <command>iproute2</command> which will cause the upgrade of Shorewall to fail with the diagnostic:
<synopsis>
error: failed dependencies:iproute is needed by shorewall-1.4.0-1
</synopsis>
This may be worked around by using the <option>--nodeps</option> option of <command>rpm</command> (<command>rpm -Uvh --nodeps <filename>your_shorewall_rpm.rpm</filename></command>).
</para>
</note>
<para>
If you are upgrading from a version < 1.4.0, then:
<itemizedlistmark="bullet">
<listitem>
<para>
The <varname>noping</varname> and <varname>forwardping</varname> interface options are no longer supported nor is the <varname>FORWARDPING</varname> option in <filename>shorewall.conf</filename>. ICMP echo-request (ping) packets are treated just like any other connection request and are subject to rules and policies.
</para>
</listitem>
<listitem>
<para>
Interface names of the form <varname><device>:<integer></varname> in <filenameclass="directory">/etc/shorewall/</filename><filename>interfaces</filename> now generate a Shorewall error at startup (they always have produced warnings in <applicationclass="software">iptables</application>).
</para>
</listitem>
<listitem>
<para>
The <varname>MERGE_HOSTS</varname> variable has been removed from <filename>shorewall.conf</filename>. Shorewall 1.4 behaves like 1.3 did when <varname>MERGE_HOSTS=Yes</varname>; that is zone contents are determined by <emphasis>BOTH</emphasis> the interfaces and hosts files when there are entries for the zone in both files.
</para>
</listitem>
<listitem>
<para>
The <varname>routestopped</varname> option in the interfaces and hosts file has been eliminated; use entries in the <filename>routestopped</filename> file instead.
</para>
</listitem>
<listitem>
<para>
The Shorewall 1.2 syntax for <varname>DNAT</varname> and <varname>REDIRECT</varname> rules is no longer accepted; you must convert to using the new syntax.
</para>
</listitem>
<listitem>
<para>
The <varname>ALLOWRELATED</varname> variable in <filename>shorewall.conf</filename> is no longer supported. Shorewall 1.4 behavior is the same as 1.3 with <varname>ALLOWRELATED=Yes</varname>.
</para>
</listitem>
<listitem>
<para>
Late-arriving DNS replies are now dropped by default; there is no need for your own <filenameclass="directory">/etc/shorewall/</filename><filename>common</filename> file simply to avoid logging these packets.
</para>
</listitem>
<listitem>
<para>
The <filename>firewall</filename>, <filename>functions</filename> and <filename>version</filename> files have been moved to <filenameclass="directory">/usr/share/shorewall</filename>.
</para>
</listitem>
<listitem>
<para>
The <filename>icmp.def</filename> file has been removed. If you include it from <filenameclass="directory">/etc/shorewall/</filename><filename>icmpdef</filename>, you will need to modify that file.
</para>
</listitem>
<listitem>
<para>
If you followed the advice in FAQ #2 and call <varname>find_interface_address</varname> in <filenameclass="directory">/etc/shorewall/</filename><filename>params</filename>, that code should be moved to <filenameclass="directory">/etc/shorewall/</filename><filename>init</filename>.
The <varname>multi</varname> interface option is no longer supported. Shorewall will generate rules for sending packets back out the same interface that they arrived on in two cases:
<itemizedlistmark="hollow">
<listitem>
<para>
There is an <emphasis>explicit</emphasis> policy for the source zone to or from the destination zone. An explicit policy names both zones and does not use the <varname>all</varname> reserved word.
</para>
</listitem>
<listitem>
<para>
There are one or more rules for traffic for the source zone to or from the destination zone including rules that use the <varname>all</varname> reserved word. Exception: if the source zone and destination zone are the same then the rule must be explicit - it must name the zone in both the <varname>SOURCE</varname> and <varname>DESTINATION</varname> columns.
Beginning in version 1.3.14, Shorewall treats entries in <filenameclass="directory">/etc/shorewall/</filename><filename>masq</filename> differently. The change involves entries with an <emphasisrole="bold">interface name</emphasis> in the <varname>SUBNET</varname> (second) <emphasisrole="bold">column</emphasis>:
<itemizedlistmark="bullet">
<listitem>
<para>
Prior to 1.3.14, Shorewall would detect the FIRST subnet on the interface (as shown by <quote>ip addr show interface</quote>) and would masquerade traffic from that subnet. Any other subnets that routed through <literal>eth1</literal> needed their own entry in <filenameclass="directory">/etc/shorewall/</filename><filename>masq</filename> to be masqueraded or to have <acronym>SNAT</acronym> applied.
</para>
</listitem>
<listitem>
<para>
Beginning with Shorewall 1.3.14, Shorewall uses the firewall's routing table to determine ALL subnets routed through the named interface. Traffic originating in ANY of those subnets is masqueraded or has SNAT applied.
</para>
</listitem>
</itemizedlist>
You will need to make a change to your configuration if:
<orderedlistnumeration="arabic">
<listitem>
<para>
You have one or more entries in <filenameclass="directory">/etc/shorewall/</filename><filename>masq</filename> with an interface name in the <varname>SUBNET</varname> (second) column; and
</para>
</listitem>
<listitem>
<para>
That interface connects to more than one subnetwork.
</para>
</listitem>
</orderedlist>
Two examples:
<examplelabel="1">
<title> Suppose that your current config is as follows:</title>
<programlisting>
<!-- I added a space below the end of the config file for clarity -->
[root@gateway test]# cat /etc/shorewall/masq
#INTERFACE SUBNET ADDRESS
eth0 eth2 206.124.146.176
eth0 192.168.10.0/24 206.124.146.176
#LAST LINE -- ADD YOUR ENTRIES ABOVE THIS LINE -- DO NOT REMOVE
[root@gateway test]# ip route show dev eth2
192.168.1.0/24 scope link
192.168.10.0/24 proto kernel scope link src 192.168.10.254
[root@gateway test]#
</programlisting>
</example>
In this case, the second entry in <filenameclass="directory">/etc/shorewall/</filename><filename>masq</filename> is no longer required.
<examplelabel="2">
<title>What if your current configuration is like this?</title>
<programlisting>
[root@gateway test]# cat /etc/shorewall/masq
#INTERFACE SUBNET ADDRESS
eth0 eth2 206.124.146.176
#LAST LINE -- ADD YOUR ENTRIES ABOVE THIS LINE -- DO NOT REMOVE
[root@gateway test]# ip route show dev eth2
192.168.1.0/24 scope link
192.168.10.0/24 proto kernel scope link src 192.168.10.254
[root@gateway test]#
</programlisting>
</example>
In this case, you would want to change the entry in /etc/shorewall/masq to:
<programlisting>
#INTERFACE SUBNET ADDRESS
eth0 192.168.1.0/24 206.124.146.176
#LAST LINE -- ADD YOUR ENTRIES ABOVE THIS LINE -- DO NOT REMOVE
</programlisting>
Version 1.3.14 also introduced simplified ICMP echo-request (ping) handling. The option <varname>OLD_PING_HANDLING=Yes</varname> in <filenameclass="directory">/etc/shorewall/</filename><filename>shorewall.conf</filename> is used to specify that the old (pre-1.3.14) ping handling is to be used (If the option is not set in your <filenameclass="directory">/etc/shorewall/</filename>shorewall.conf then <varname>OLD_PING_HANDLING=Yes</varname> is assumed). I don't plan on supporting the old handling indefinitely so I urge current users to migrate to using the new handling as soon as possible. See the 'Ping' handling documentation for details.
The <filename>functions</filename> file has moved to <filenameclass="directory">/usr/lib/shorewall/</filename><filename>functions</filename>. If you have an application that uses functions from that file, your application will need to be changed to reflect this change of location.
If you have a pair of firewall systems configured for failover or if you have asymmetric routing, you will need to modify your firewall setup slightly under Shorewall versions >= 1.3.8. Beginning with version 1.3.8, you must set <varname>NEWNOTSYN=Yes</varname> in your <filenameclass="directory">/etc/shorewall/</filename><filename>shorewall.conf</filename> file.
Users specifying <varname>ALLOWRELATED=No</varname> in <filenameclass="directory">/etc/</filename><filename>shorewall.conf</filename> will need to include the following rules in their <filenameclass="directory">/etc/shorewall/</filename><filename>icmpdef</filename> file (creating this file if necessary):
<programlisting>
run_iptables -A icmpdef -p ICMP --icmp-type echo-reply -j ACCEPT
run_iptables -A icmpdef -p ICMP --icmp-type source-quench -j ACCEPT
run_iptables -A icmpdef -p ICMP --icmp-type destination-unreachable -j ACCEPT
run_iptables -A icmpdef -p ICMP --icmp-type time-exceeded -j ACCEPT
run_iptables -A icmpdef -p ICMP --icmp-type parameter-problem -j ACCEPT
</programlisting>
Users having an <filenameclass="directory">/etc/shorewall/</filename><filename>icmpdef</filename> file may remove the <command>./etc/shorewall/icmp.def</command> command from that file since the <filename>icmp.def</filename> file is now empty.
<title>Upgrading Bering to Shorewall >= 1.3.3</title>
<itemizedlist>
<listitem>
<para>
To properly upgrade with Shorewall version 1.3.3 and later:
<orderedlistnumeration="arabic">
<listitem>
<para>
Be sure you have a backup -- you will need to transcribe any Shorewall configuration changes that you have made to the new configuration.
</para>
</listitem>
<listitem>
<para>
Replace the <filename>shorwall.lrp</filename> package provided on the Bering floppy with the later one. If you did not obtain the later version from Jacques's site, see additional instructions below.
</para>
</listitem>
<listitem>
<para>
Edit the <filenameclass="directory">/var/lib/lrpkg/</filename><filename>root.exclude.list</filename> file and remove the <filename>/var/lib/shorewall</filename> entry if present. Then do not forget to backup <filename>root.lrp</filename>!
</para>
</listitem>
</orderedlist>
The .lrp that I release isn't set up for a two-interface firewall like Jacques's. You need to follow the instructions for setting up a two-interface firewall plus you also need to add the following two Bering-specific rules to <filenameclass="directory">/etc/shorewall/</filename><filename>rules</filename>:
If you have a pair of firewall systems configured for failover or if you have asymmetric routing, you will need to modify your firewall setup slightly under Shorewall versions 1.3.6 and 1.3.7
<orderedlist>
<listitem>
<para>
Create the file <filenameclass="directory">/etc/shorewall/</filename><filename>newnotsyn</filename> and in it add the following rule:
<!-- The following code wraps off of the document. I have added the comment above the command. -->
<programlisting>
# So that the connection tracking table can be rebuilt
# from non-SYN packets after takeover.
run_iptables -A newnotsyn -j RETURN
</programlisting>
</para>
</listitem>
<listitem>
<para>
Create <filenameclass="directory">/etc/shorewall/</filename><filename>common</filename> (if you don't already have that file) and include the following:
<programlisting>
#Accept Acks to rebuild connection tracking table.
run_iptables -A common -p tcp --tcp-flags ACK,FIN,RST ACK -j ACCEPT
The functions and versions files together with the <filenameclass="symlink">firewall</filename> symbolic link have moved from <filenameclass="directory">/etc/shorewall</filename> to <filenameclass="directory">/var/lib/shorewall</filename>. If you have applications that access these files, those applications should be modified accordingly.
