Linux IPX HOWTO

15. IPX tunnel over IP

Many of you will be in a situation where you have two Novell Local Area Netorks with only an IP connection between them. How do you play multiplayer deathmatch DOOM for DOS via this arrangement you might ask ? Andreas Godzina <ag at agsc.han.de> has an answer for you in the form of ipxtunnel.

ipxtunnel provides a bridge-like facility for IPX by allowing IPX packets to be encapsulated with tcp/ip datagrams so that they can be carried by a tcp/ip connection. It listens for IPX packets and when it hears one it wraps it within a tcp/ip datagram and routes it to a remote IP address that you specify. For this to work of course the machine that you route the encapsulated IPX must also be running a copy of the same version of ipxtunnel as you.

15.1 Obtaining ipxtunnel

You can obtain ipxtunnel from sunsite.unc.edu or mirror sites.

15.2 Building ipxtunnel

ipxtunnel built cleanly for me using the following commands:

# cd /usr/src
# tar xvfz .../ipxtunnel.tgz
# cd ipxtunnel
# make

15.3 Configuring ipxtunnel

Configuration for ipxtunnel is easy. Lets say that your friends machine is gau.somewhere.com and your machine is called gim.sw.edu. ipxtunnel uses a configuration file called /etc/ipxtunnel.conf. This file allows you to specify the default UDP port to use for the tcp/ip connection, where to send the encapsulated data and which of your local interfaces ipxtunnel should listen on and deliver IPX packets to.

A simple configuration file would look like the following:

#
# /etc/ipxtunnel.conf for gim.sw.edu
#
# The UDP port to use:                       (default 7666)
port 7777
#
# The remote machine to send IPX packets to: (no default)
remote gau.somewhere.com
#
# The local interfaces to listen for IPX on: (default eth0)
interface eth0
interface eth1

15.4 Testing and using ipxtunnel

ipxtunnel acts like an IPX bridge, so the IPX networks at either end of the link should probably be the same. Andreas has never tested the ipxtunnel in an environment that actually supports Novell file servers so if you do try this in a real environment let Andreas know if it works or not.

If the ipxtunnel is working you should be able to start your DOOM machines up at each end of the link running IPX mode and they should see each other.

Andreas has only used this code over good high speed lines and he makes no claim as to its performance when your link is low speed. Again, let him know what works for you and what doesn't.