mirror of
https://gitlab.com/shorewall/code.git
synced 2024-12-29 17:48:53 +01:00
888f9351b5
git-svn-id: https://shorewall.svn.sourceforge.net/svnroot/shorewall/trunk@4027 fbd18981-670d-0410-9b5c-8dc0c1a9a2bb
125 lines
4.9 KiB
Plaintext
125 lines
4.9 KiB
Plaintext
Shoreline Firewall configuration generator
|
|
(c) Copyright 2004-2006 Paul D. Gear <paul@gear.dyndns.org>
|
|
|
|
This program is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation; either version 2 of the License, or
|
|
(at your option) any later version.
|
|
|
|
This program is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program; if not, write to the Free Software
|
|
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
|
|
|
|
SHOREWALL
|
|
|
|
The quick plug:
|
|
|
|
- Shorewall is the only firewall i trust.
|
|
|
|
The IT Manager plug:
|
|
|
|
- Shorewall is a policy-driven firewall which lets you think about your
|
|
firewall at a higher level than iptables commands.
|
|
|
|
The hard sell to you crazy people still maintaining manual firewall scripts:
|
|
|
|
- Shorewall is a wrapper around the kernel iptables, so your existing
|
|
Linux firewall skills transfer. I converted from a 900-plus-line
|
|
ipchains shell script to around 50 lines of shorewall configuration in
|
|
less than 4 hours, with no prior experience.
|
|
|
|
|
|
ISSUES
|
|
|
|
- I'm paranoid - i want more than one firewall between me and the world.
|
|
|
|
- Configuring multiple firewalls separately is a recipe for getting your
|
|
rules out of sync, and allowing security problems to creep in.
|
|
|
|
- IT Manager types (like me) like to know their policy is consistently
|
|
implemented.
|
|
|
|
|
|
SOLUTION
|
|
|
|
Shoregen is a script that generates shorewall configurations for multiple
|
|
firewalls from a common set of rules and policies. Only the minimal
|
|
information necessary for operation is stored on each firewall, so, for
|
|
example, your DMZ server doesn't need to know about the rules on your
|
|
internal network, but at the same time, it gets consistent rules to your
|
|
outer guard.
|
|
|
|
|
|
PHILOSOPHY
|
|
|
|
Shoregen assumes the X-Files approach to firewall design: trust no one.
|
|
That is, paranoia is a virtue. All access should be as limited as possible
|
|
for things to work. If you don't already agree with this philosophy, you
|
|
may find some of the things shoregen does frustrating, but then again,
|
|
you're probably not reading this document. :-)
|
|
|
|
|
|
DESIGN
|
|
|
|
Shoregen distinguishes between two different types of shorewall
|
|
configuration files. Most shorewall configuration files are simply
|
|
concatenated together from parts constructed from common and host-specific
|
|
parts. These are called simple configs; shoregen doesn't substantially
|
|
alter them, and uses little information from them.
|
|
|
|
Configs with which shoregen is more concerned are treated separately, and
|
|
additional features beyond the scope of shorewall itself are implemented.
|
|
Most importantly, two new policy/rule keywords are introduced: WARN and
|
|
BAN. These keywords are not included in shoregen's output, but when a
|
|
subsequent rule or policy is encountered which matches a rule or policy
|
|
marked WARN or BAN, an error message is issued. In the case of BAN, the
|
|
offending line is also dropped from the output, and a non-zero return code
|
|
issued.
|
|
|
|
|
|
PREREQUISITES
|
|
|
|
The tools you will need to use shoregen are:
|
|
perl The main shoregen script is written in Perl
|
|
rsync Used to keep /etc/shorewall directories on your firewalls
|
|
in sync with the central repository
|
|
ssh Encrypted transport for rsync
|
|
make Optional, but saves a few keystrokes.
|
|
|
|
|
|
USAGE
|
|
|
|
Put shoregen and install_shoregen in a directory on your PATH.
|
|
|
|
Make a central directory for your configs. I recommend somewhere in a
|
|
trusted user's home directory or central system admin repository. This
|
|
directory should be on a trusted machine in the most secure part of your
|
|
network. Put all of your policies, rules, and zones together in the
|
|
correct order in files in the top level of this directory.
|
|
|
|
For each of the simple configs you want to generate centrally, create a
|
|
directory, with a file called COMMON (if necessary) containing the content
|
|
you want to see in that file on all hosts, and a file named for each host
|
|
for host-specific content. I recommend that the default shorewall
|
|
configuration file be placed in the COMMON file of the corresponding
|
|
directory, with directives that are not appropriate commented out.
|
|
|
|
When shoregen is run, it places the generated files in the directory
|
|
SPOOL/<host>, where <host> is the hostname of the target firewall. The
|
|
files in this directory are synchronised and the firewall checked and/or
|
|
restarted by a simple wrapper script called install_shoregen.
|
|
|
|
See the samples directory for a starting point configuration. It provides
|
|
some suggested policies & rules for the network shown in example1.png. The
|
|
sample configuration has not been tested in any way.
|
|
|
|
I hope you find shoregen useful. I welcome your comments, contributions,
|
|
criticisms, and questions.
|
|
|