[PLUG] chat softwares

AthlonRob AthlonRob at axpr.net
Tue Dec 2 21:56:02 UTC 2003


On Tue, 2003-12-02 at 21:21, Billy Dimaculangan wrote:

> anyone who could help me on how to block through iptables the chat software
> and yahoo/msn messenger. sample configs or refence link would be greatly
> appreciated.

Figure out what ports they're using (there are many ways to do this, the
easiest probably being firing up GAIM and seeing what it connects to)
then block 'em on the PREROUTE table-

iptables -t nat -A PREROUTE -p tcp --dport 1863 -j DROP

... for example, should kill MSN messenger on its default port.  I'm
pretty sure it uses TCP, but you might block UDP, too, in case.  It
looks like YIM uses port 5050 by default.  You could block on the
destination IP address, too.. but in my experience, those kinds of
things change with time.

That is, of course, assuming you mean how to stop systems using a linux
box as the default gateway.

Rob





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