This document describes how to enable the Linux IP Masquerade feature on a
given Linux host. IP Masquerade, called "IPMASQ" or "MASQ" for short, is a form
of Network Address Translation (NAT) which allows internally connected computers
that do not have one or more registered Internet IP addresses to communicate to
the Internet via the Linux server's Internet IP address. Since IPMASQ is a
generic technology, you can connect the Linux server's internal and external
to other computers through LAN technologies like Ethernet, TokenRing, and FDDI,
as well as dialup connections line PPP or SLIP links. This document primarily
uses Ethernet and PPP connections in examples because it is most commonly used
with DSL / Cablemodems and dialup connections.
"This document is intended for systems running stable Linux kernels like 2.4.x,
2.2.x, and 2.0.x preferably on an IBM-compatible PC. IP Masquerade
does work on other Linux-supported platforms like Sparc, Alpha, PowerPC, etc.
but this HOWTO doesn't cover them in as much detail. Beta kernels
such as 2.5.x, 2.3.x, 2.1.x, and ANY kernels less than 2.0.x are NOT covered
in this document. The primary reason for this is because many of the older
kernels are considered broken. If you are using an older kernel version, it
is highly advisable to upgrade to one of the stable Linux kernels before using
IP Masquerading. "
