Shorewall Support Guide

Tom Eastep

Copyright © 2001-2005 Thomas M. Eastep

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 “GNU Free Documentation License”.

Important

Problem reports that do not include the information requested in the Problem Reporting Guidelines below will not be answered by the Shorewall author.

2006-04-20


Table of Contents

Before Reporting a Problem or Asking a Question
Problem Reporting Guidelines
When using the mailing list, please post in plain text
Where to Send your Problem Report or to Ask for Help
Subscribing to the Users Mailing List
Subscribing to the Announce Mailing List
Subscribing to the Development Mailing List
Other Mailing Lists

Before Reporting a Problem or Asking a Question

There are a number of sources of Shorewall information. Please try these before you post.

  • The two currently-supported Shorewall major releases are 3.0 and 3.2.

    Note

    Shorewall versions earlier than 3.0.0 are no longer supported; we will try to help but we will not supply fixes for bugs nor will we spend time reading old code to try to help solve your problems with these old releases.

  • More than half of the questions posted on the support list have answers directly accessible from the Documentation Index

  • The FAQ has solutions to more than 40 common problems.

  • The Troubleshooting Information contains a number of tips to help you solve common problems.

Problem Reporting Guidelines

Please refer to the following flowchart to guide you through the problem reporting process.

  1. If your problem is that an error occurs when you try to “shorewall start” or if Shorewall is otherwise failing to start properly, then please:

    /sbin/shorewall trace start 2> /tmp/trace

    Forward the /tmp/trace file as an attachment (you may compress it if you like).

  2. If you are unsure if Shorewall is starting successfully or not then first note that if Shorewall starts successfully, the last message it produces is "Shorewall Started":

    …
Activating Rules...
Shorewall Started
gateway:~#

    If you are seeing this message then Shorewall is starting successfully.

    If you are still unsure if Shorewall is starting or not, enter the following command:

    /sbin/shorewall show shorewall

    If Shorewall has started successfully, you will see output similar to this:

    Shorewall-2.2.3 Chain shorewall at gateway - Wed Apr 20 14:41:53 PDT 2005

Counters reset Sat Apr 16 17:35:06 PDT 2005

Chain shorewall (0 references)
 pkts bytes target     prot opt in     out     source               destination

    If Shorewall has not started properly, you will see output similar to this:

    Shorewall-2.2.3 Chain shorewall at gateway - Wed Apr 20 14:43:13 PDT 2005

Counters reset Sat Apr 16 17:35:06 PDT 2005

iptables: No chain/target/match by that name

  3. If Shorewall is starting successfully and your problem is that some set of connections to/from or through your firewall isn't working (examples: local systems can't access the internet, you can't send email through the firewall, you can't surf the web from the firewall, etc.) then please perform the following six steps:

    1. If Shorewall isn't started then /sbin/shorewall start. Otherwise /sbin/shorewall reset.

    2. Try making the connection that is failing.

    3. /sbin/shorewall status > /tmp/status.txt

    4. Post the /tmp/status.txt file as an attachment (you may compress it if you like).

    5. Describe where you are trying to make the connection from (IP address) and what host (IP address) you are trying to connect to.

    6. Please do not edit the diagnostic information in an attempt to conceal your IP address, netmask, nameserver addresses, domain name, etc. These aren't secrets, and concealing them often misleads us and may prevent your problem from being looked at all together.

  4. Otherwise please include the following information:

    • the exact version of Shorewall you are running.

      /sbin/shorewall version

    • the complete exact output of

      ip addr show

    • the complete exact output of

      ip route show

  • Please remember we only know what is posted in your message. Do not leave out any information that appears to be correct, or was mentioned in a previous post. There have been countless posts by people who were sure that some part of their configuration was correct when it actually contained a small error. We tend to be skeptics where detail is lacking.

  • Please keep in mind that you're asking for free technical support. Any help we offer is an act of generosity, not an obligation. Try to make it easy for us to help you. Follow good, courteous practices in writing and formatting your e-mail. Provide details that we need if you expect good answers. Exact quoting of error messages, log entries, command output, and other output is better than a paraphrase or summary.

  • Please give details about what doesn't work. Reports that say “I followed the directions and it didn't work” will elicit sympathy but probably little in the way of help. Again -- if ping from A to B fails, say so (and see below for information about reporting “ping” problems). If Computer B doesn't show up in “Network Neighborhood” then say so. If access by IP address works but by DNS names it doesn't then say so.

  • Please don't describe your environment and then ask us to send you custom configuration files. We're here to answer your questions but we can't do your job for you.

  • Please do NOT include the output of iptables -L — the output of shorewall show or shorewall status is much more useful.

  • As a general matter, please do not edit the diagnostic information in an attempt to conceal your IP address, netmask, nameserver addresses, domain name, etc. These aren't secrets, and concealing them often misleads us (and 80% of the time, a hacker could derive them anyway from information contained in the SMTP headers of your post).

  • Do you see any “Shorewall” messages (“/sbin/shorewall show log”) when you exercise the function that is giving you problems? If so, include the message(s) in your post along with a copy of your /etc/shorewall/interfaces file (and /etc/shorewall/hosts file if you have entries in that file).

  • Please include any of the Shorewall configuration files (especially the /etc/shorewall/hosts file if you have modified that file) that you think are relevant. If you include /etc/shorewall/rules, please include /etc/shorewall/policy as well (rules are meaningless unless one also knows the policies).

  • The list server limits posts to 120kb so don't post graphics of your network layout, etc. to the Mailing List -- your post will be rejected.

  • The author gratefully acknowleges that the above list was heavily plagiarized from the excellent LEAF document by Ray Olszewski found at http://leaf-project.org/pub/doc/docmanager/docid_1891.html.

When using the mailing list, please post in plain text

A growing number of MTAs serving list subscribers are rejecting all HTML traffic. At least one MTA has gone so far as to blacklist shorewall.net “for continuous abuse” because it has been my policy to allow HTML in list posts!!

I think that blocking all HTML is a Draconian way to control spam and that the ultimate losers here are not the spammers but the list subscribers whose MTAs are bouncing all shorewall.net mail. As one list subscriber wrote to me privately “These e-mail admin's need to get a (expletive deleted) life instead of trying to rid the planet of HTML based e-mail”. Nevertheless, to allow subscribers to receive list posts as must as possible, I have now configured the list server at shorewall.net to convert all HTML to plain text. Sometimes the conversion process fails in which case, the post sent to the list is empty. Even when conversion succeeds, the converted post is difficult to read so all of us will appreciate it if you just post in plain text to begin with.

Where to Send your Problem Report or to Ask for Help

If you run the current development release and your question involves a feature that is only available in the development release (see the Shorewall Release Model page) -- please post your question or problem to the Shorewall Development Mailing List. IMPORTANT: You must subscribe to the list before you will be able to post to it (see link below).

If you run Shorewall under MandrakeSoft Multi Network Firewall (MNF) and you have not purchased an MNF license from MandrakeSoft then you can post non MNF-specific Shorewall questions to the Shorewall users mailing list. Do not expect to get free MNF support on the list.

Otherwise, please post your question or problem to the Shorewall users mailing list. IMPORTANT: You must subscribe to the list before you will be able to post to it (see link below).

For quick questions, there is also a #shorewall channel at irc.freenode.net.

Subscribing to the Users Mailing List

To Subscribe to the users mailing list go to https://lists.sourceforge.net/lists/listinfo/shorewall-users.

Subscribing to the Announce Mailing List

To Subscribe to the announce mailing list (low-traffic,read only) go to:

https://lists.sourceforge.net/lists/listinfo/shorewall-announce

Subscribing to the Development Mailing List

To Subscribe to the development mailing list go to https://lists.sourceforge.net/lists/listinfo/shorewall-devel.

Other Mailing Lists

For information on other Shorewall mailing lists, go to http://sourceforge.net/mail/?group_id=22587 .