Block Skype with PF

Greg Armer wiqd at
Mon Sep 11 04:38:13 PDT 2006

Good day list,

I was just wondering if any of you have a running 'receipe' using PF
that can block Skype.

What I have found out is the following:

- Skype picks a random port to use when it is installed
- It can switch over to port 80 / 443 if a firewall is too restrictive
- It appears UDP ports above 1024 are used aswell

So what I was thinking of doing is blocking all outgoing UDP above port
1024, and trying to identify and block the port 80 / 442 traffic with 
squid and a transparent proxy.

Does anyone have any better solutions to this which do not involve
expensive layer 7 inspection hardware ?

Many thanks for your comments / ideas.


Greg Armer

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