What is it?
The Shoreline Firewall, more commonly known as "Shorewall", is
a Netfilter (iptables)
based firewall that can be used on a dedicated
firewall system, a multi-function gateway/router/server
or on a standalone GNU/Linux system.
This program is free software; you can redistribute it and/or modify
it under the terms of Version 2 of the GNU
General Public License as published by the Free Software
Foundation.
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., 675 Mass Ave, Cambridge, MA 02139, USA
Copyright 2001, 2002, 2003 Thomas M. Eastep
This is the Shorewall 1.4 Web Site
The information on this site applies only to 1.4.x releases of Shorewall.
For older versions:
Getting Started with Shorewall
New to Shorewall? Start by selecting the
QuickStart
Guide that most closely match your environment and follow
the step by step instructions.
Looking for Information?
The Documentation
Index is a good place to start as is the Quick Search to your right.
Running Shorewall on Mandrake with a two-interface setup?
If so, the documentation on this site will
not apply directly to your setup. If you want to use the documentation
that you find here, you will want to consider uninstalling what you have
and installing a setup that matches the documentation on this site.
See the Two-interface QuickStart Guide
for details.
News
7/15/2003 - New Mirror in Brazil
Thanks to the folks at securityopensource.org.br, there is now a Shorewall
mirror in Brazil.
7/15/2003 - Shorewall-1.4.6 RC 1
http://shorewall.net/pub/shorewall/testing
ftp://shorewall.net/pub/shorewall/testing
Problems Corrected:
- A problem seen on RH7.3 systems where Shorewall encountered
start errors when started using the "service" mechanism has been worked
around.
- Where a list of IP addresses appears in the DEST column of
a DNAT[-] rule, Shorewall incorrectly created multiple DNAT rules in the
nat table (one for each element in the list). Shorewall now correctly creates
a single DNAT rule with multiple "--to-destination" clauses.
- Corrected a problem in Beta 1 where DNS names containing
a "-" were mis-handled when they appeared in the DEST column of a rule.
- A number of problems with rule parsing have been
corrected. Corrections involve the handling of "z1!z2" in the SOURCE column
as well as lists in the ORIGINAL DESTINATION column.
Migration Issues:
- In earlier versions, an undocumented feature allowed entries
in the host file as follows:
z eth1:192.168.1.0/24,eth2:192.168.2.0/24
This capability was never documented and has been removed in 1.4.6 to
allow entries of the following format:
z eth1:192.168.1.0/24,192.168.2.0/24
- The NAT_ENABLED, MANGLE_ENABLED and MULTIPORT options have
been removed from /etc/shorewall/shorewall.conf. These capabilities are
now automatically detected by Shorewall (see below).
New Features:
- A 'newnotsyn' interface option has been added. This option
may be specified in /etc/shorewall/interfaces and overrides the setting
NEWNOTSYN=No for packets arriving on the associated interface.
- The means for specifying a range of IP addresses in /etc/shorewall/masq
to use for SNAT is now documented. ADD_SNAT_ALIASES=Yes is enabled for
address ranges.
- Shorewall can now add IP addresses to subnets other than
the first one on an interface.
- DNAT[-] rules may now be used to load balance (round-robin)
over a set of servers. Servers may be specified in a range of addresses
given as <first address>-<last address>.
Example:
DNAT net loc:192.168.10.2-192.168.10.5 tcp 80
- The NAT_ENABLED, MANGLE_ENABLED and MULTIPORT configuration
options have been removed and have been replaced by code that detects whether
these capabilities are present in the current kernel. The output of the
start, restart and check commands have been enhanced to report the outcome:
Shorewall has detected the following iptables/netfilter capabilities:
NAT: Available
Packet Mangling: Available
Multi-port Match: Available
Verifying Configuration...
- Support for the Connection Tracking Match Extension has been
added. This extension is available in recent kernel/iptables releases
and allows for rules which match against elements in netfilter's connection
tracking table. Shorewall automatically detects the availability of this
extension and reports its availability in the output of the start, restart
and check commands.
Shorewall has detected the following iptables/netfilter capabilities:
NAT: Available
Packet Mangling: Available
Multi-port Match: Available
Connection Tracking Match: Available
Verifying Configuration...
If this extension is available, the ruleset generated by Shorewall
is changed in the following ways:
- To handle 'norfc1918' filtering, Shorewall will not create
chains in the mangle table but will rather do all 'norfc1918' filtering
in the filter table (rfc1918 chain).
- Recall that Shorewall DNAT rules generate two netfilter
rules; one in the nat table and one in the filter table. If the Connection
Tracking Match Extension is available, the rule in the filter table is extended
to check that the original destination address was the same as specified
(or defaulted to) in the DNAT rule.
- The shell used to interpret the firewall script (/usr/share/shorewall/firewall)
may now be specified using the SHOREWALL_SHELL parameter in shorewall.conf.
- An 'ipcalc' command has been added to /sbin/shorewall.
ipcalc [ <address> <netmask> | <address>/<vlsm>
]
Examples:
[root@wookie root]# shorewall ipcalc 192.168.1.0/24
CIDR=192.168.1.0/24
NETMASK=255.255.255.0
NETWORK=192.168.1.0
BROADCAST=192.168.1.255
[root@wookie root]#
[root@wookie root]# shorewall ipcalc 192.168.1.0 255.255.255.0
CIDR=192.168.1.0/24
NETMASK=255.255.255.0
NETWORK=192.168.1.0
BROADCAST=192.168.1.255
[root@wookie root]#
Warning:
If your shell only supports 32-bit signed arithmatic (ash or dash),
then the ipcalc command produces incorrect information for IP addresses
128.0.0.0-1 and for /1 networks. Bash should produce correct information
for all valid IP addresses.
- An 'iprange' command has been added to /sbin/shorewall.
iprange <address>-<address>
This command decomposes a range of IP addressses into a list of network
and host addresses. The command can be useful if you need to construct
an efficient set of rules that accept connections from a range of network
addresses.
Note: If your shell only supports 32-bit signed arithmetic (ash or dash)
then the range may not span 128.0.0.0.
Example:
[root@gateway root]# shorewall iprange 192.168.1.4-192.168.12.9
192.168.1.4/30
192.168.1.8/29
192.168.1.16/28
192.168.1.32/27
192.168.1.64/26
192.168.1.128/25
192.168.2.0/23
192.168.4.0/22
192.168.8.0/22
192.168.12.0/29
192.168.12.8/31
[root@gateway root]#
- A list of host/net addresses is now allowed in an entry in
/etc/shorewall/hosts.
Example:
foo eth1:192.168.1.0/24,192.168.2.0/24
6/17/2003 - Shorewall-1.4.5
Problems Corrected:
- The command "shorewall debug try <directory>"
now correctly traces the attempt.
- The INCLUDE directive now works properly in the zones
file; previously, INCLUDE in that file was ignored.
- /etc/shorewall/routestopped records with an empty
second column are no longer ignored.
New Features:
- The ORIGINAL DEST column in a DNAT[-] or REDIRECT[-]
rule may now contain a list of addresses. If the list begins with "!'
then the rule will take effect only if the original destination address
in the connection request does not match any of the addresses listed.
6/15/2003 - Shorewall, Kernel 2.4.21 and iptables 1.2.8
The firewall at shorewall.net has been upgraded to the 2.4.21
kernel and iptables 1.2.8 (using the "official" RPM from netfilter.org).
No problems have been encountered with this set of software. The Shorewall
version is 1.4.4b plus the accumulated changes for 1.4.5.
6/8/2003 - Updated Samples
Thanks to Francesca Smith, the samples have been updated to Shorewall
version 1.4.4.
More News
Jacques Nilo and Eric
Wolzak have a LEAF (router/firewall/gateway
on a floppy, CD or compact flash) distribution
called Bering that
features Shorewall-1.4.2 and Kernel-2.4.20.
You can find their work at:
http://leaf.sourceforge.net/devel/jnilo
Congratulations to Jacques
and Eric on the recent release of Bering
1.2!!!
This site is hosted by the generous folks at SourceForge.net
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