Blocking an arbitrary port with ipfwadm

[Damon Muller <damon@empire.net.au>]

Hi Folks,

Not sure if this has been covered before, and it isn't 100%
debian-specific, but I thought some ipfwadm guru out there might be able
to help a poor clueless idiot such as myself.

What I want to do is use ipfwadm to block a single port - namely 31337 
(UDP). For anyone who has had their head in the sand for the last few
months, that's the port that Back Orrifice listens on by default.

This isn't meant to be a full-on firewall at the moment, but I'd
specifically like to block that port so someone doesn't hijack the
Windoze machines of some of our more clueless ppp users.

Any pointers would be very helpful (please don't just say RTFM - I did,
but it didn't make too much sense to me).

Thanks,

damon

--
Damon Muller              | Did a large procession wave their torches
(damon@empire.net.au)     | As my head fell in the basket,
Network Administrator     | And was everyone dancing on the casket...
EmpireNET                 |                      - TBMG, "Dead"