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Text file for ipddp.c:

        AppleTalk-IP Decapsulation and AppleTalk-IP Encapsulation

This text file is written by Jay Schulist 

Introduction

------------

AppleTalk-IP (IPDDP) is the method computers connected to AppleTalk

networks can use to communicate via IP. AppleTalk-IP is simply IP datagrams

inside AppleTalk packets.

Through this driver you can either allow your Linux box to communicate

IP over an AppleTalk network or you can provide IP gatewaying functions

for your AppleTalk users.

You can currently encapsulate or decapsulate AppleTalk-IP on LocalTalk,

EtherTalk and PPPTalk. The only limit on the protocol is that of what

kernel AppleTalk layer and drivers are available.

Each mode requires its own user space software.

Compiling AppleTalk-IP Decapsulation/Encapsulation

=================================================

AppleTalk-IP decapsulation needs to be compiled into your kernel. You

will need to turn on AppleTalk-IP driver support. Then you will need to

select ONE of the two options; IP to AppleTalk-IP encapsulation support or

AppleTalk-IP to IP decapsulation support. If you compile the driver

statically you will only be able to use the driver for the function you have

enabled in the kernel. If you compile the driver as a module you can

select what mode you want it to run in via a module loading param.

ipddp_mode=1 for AppleTalk-IP encapsulation and ipddp_mode=2 for

AppleTalk-IP to IP decapsulation.

Basic instructions for user space tools

=======================================

To enable AppleTalk-IP decapsulation/encapsulation you will need the

proper tools. You can get the tools for decapsulation from

http://spacs1.spacs.k12.wi.us/~jschlst/index.html and for encapsulation

from http://www.maths.unm.edu/~bradford/ltpc.html

I will briefly describe the operation of the tools, but you will

need to consult the supporting documentation for each set of tools.

Decapsulation - You will need to download a software package called

MacGate. In this distribution there will be a tool called MacRoute

which enables you to add routes to the kernel for your Macs by hand.

Also the tool MacRegGateWay is included to register the

proper IP Gateway and IP addresses for your machine. Included in this

distribution is a patch to netatalk-1.4b2+asun2.0a17.2 (available from

ftp.u.washington.edu/pub/user-supported/asun/) this patch is optional

but it allows automatic adding and deleting of routes for Macs. (Handy

for locations with large Mac installations)

Encapsulation - You will need to download a software daemon called ipddpd.

This software expects there to be an AppleTalk-IP gateway on the network.

You will also need to add the proper routes to route your Linux box's IP

traffic out the ipddp interface.

Common Uses of ipddp.c

----------------------

Of course AppleTalk-IP decapsulation and encapsulation, but specifically

decapsulation is being used most for connecting LocalTalk networks to

IP networks. Although it has been used on EtherTalk networks to allow

Macs that are only able to tunnel IP over EtherTalk.

Encapsulation has been used to allow a Linux box stuck on a LocalTalk

network to use IP. It should work equally well if you are stuck on an

EtherTalk only network.

Further Assistance

-------------------

You can contact me (Jay Schulist ) with any

questions regarding decapsulation or encapsulation. Bradford W. Johnson

 originally wrote the ipddp.c driver for IP

encapsulation in AppleTalk.