[ILUG] ipmasqing and Quake

[kevin lyda]

On Wed, Apr 25, 2001 at 01:15:10PM +0100, Steffen Higel wrote:
> Some applications like Quake or ICQ need specific modules to work with
> ipmasqing. I get how ipmasqing works, but how do the packets sent out by
> said applications differ from say, telnet or http, that they require this
> sort of modification?

it's because the protocol in question makes reference to the layer
below it.  so when quake data is streaming between the server and client,
it makes reference to the ip address (and maybe the tcp port) being used
by the client.  the quake ipmasq module has to grab that part of the
protocol and replace it with the ip address (and tcp port if required)
being used by the masq'ing box since that's what the server sees.

ftp is a rather simple protocol that also suffers from this problem.
if you're bored, get the ftp rc, open up two xterms and use nc to connect
to an ftp server (reachable w/o masq'ing).  in the other xterm you can
open the tcp/ip port to listen on to receive data, and then use that
for the port command of the first xterm.  playing with it you'll see
why those modules are needed.

kevin

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