ipmasq
ipmasq
is a system to securely initialize IP Masquerade for use as
a forwarding firewall. IP Masquerade is a feature of the Linux kernel that
allows an entire network of computers to be connected to another network
(usually the Internet) with only one network address on that other network. IP
Masquerade is often referred to as NAT (Network Address Translation) on other
platforms.
ipmasq
started life in the author's dorm room as an instance of
the strong ruleset described in the ipmasq
mini-HOWTO
. This was christened the 1.x series, as it grew it
became more robust. However, it only supported the 2.0 kernels, as it used
ipfwadm
, and hardcoded the author's dorm room network.
The 2.x series of ipmasq
saw its generalization via a
configuration file and its introduction into the Debian distribution.
The 3.0 release of ipmasq
was the first release suitable for use
with pppd
. It received some much needed intelligence about
interfaces and routes, which allowed it to cope with changing network
connections. Also, version 3.0 introduced support for the
ipchains
interface which appears in the 2.2 and the later 2.1
series kernels.
Later releases of the 3.x series added other features. Version 3.1.0 added the flexible rules framework, while version 3.3.0 added infrastructure for loading of ip_masq_* kernel modules.
This document first appeared in version 3.4.0 of ipmasq
.
The 3.5 series of ipmasq
added support for debconf
,
Debian's next-generation configuration management system. It also added
support for the netfilter kernel interface found in later 2.3 and 2.4 kernels.
For more information about netfilter, please see http://netfilter.kernelnotes.org/
.
ipmasq
requires the kernel be built with masquerading support.
The specific kernel options for each major kernel revision are listed below.
Kernel versions 2.0.0 through 2.1.100
Kernels 2.1.101 through later 2.3 releases
Later 2.3 kernel versions through 2.4
More information about IP Masquerade can be found at the Linux IP Masquerade
Resource, http://ipmasq.cjb.net/
.
Ipmasq User's Manual
Brian Bassettbrianb@debian.org