IM file transfers with iptables

["Jeff Bonner" <jeff@integralogic.com>]

I'm having great difficulty figuring out what I need to get file
transfers working with AIM and ICQ clients on my LAN, when using
iptables and masquerading through the firewall.  There seems to be a lot
of conflicting information, and none of it has worked for me.

Some people suggest using:

  iptables -t nat -A PREROUTING -p tcp -I eth0 --dport 5190 -j DNAT \
       --to-destination 192.168.0.2

There are also references to the old way of doing it with the ipchains
legacy support and/or ipmasqadm portfw, which I'd like to avoid
altogether.  I guess the best way (?) to get it working is with a kernel
module, but it's my understanding that one has not yet been written (or
ported from 2.2) for this purpose.

Can anyone supply me with a working snippet of code?

Thanks in advance,

Jeff Bonner
Royal Oak MI USA

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