SV: Blocking IRC Access

[Thomas Westlund <thomas.westlund () prioritytelecom no>]

Since you in theory can run IRC on any port you want, depending on the
configuration of the IRC server of course, just blocking
the ports would not let you stop all IRC traffic.

I'm not quite shure about cisco equiptment, but FW-1 (and I'm shure a lot of
others) lets you make a rule based on a packet matching pattern.
This will let you filter out IRC traffic regardless of the port's the
session is running on.

I've never built a pattern for stopping IRC, but if you google it I'm shure
you'll find someone who has.

Hope this points you in the right direction :)

-- 
Thomas Westlund
Priority Telecom Norway AS 



-----Opprinnelig melding-----
Fra: Mike [mailto:mjcarter () ihug co nz]
Sendt: 17.11.2003 08:46
Til: security-basics () securityfocus com
Emne: Blocking IRC Access


Hi All,
I'm looking at moving my career towards security, so was interested when I
received an email from our security department that stated they would be
blocking IRC by closing ports 6665-6669.

I would have thought a lot more ports would need to be closed if the secops
wanted to completely block IRC.

What is the "best" way to disable access to IRC?

Block known ports, what ports would need to be blocked?

Or just drop packets, how would that be done?

We use Cisco equipment and are primarily a win2k 70% winxp 30% site

Like I said I'm wanting to move into security, but at the moment I wouldn't
even class myself as a novice.

Any input I could get from this list will be very much appreciated!

Thanks
Mike



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