Firewall rules to block unwanted protocolls on given ports

[johhny_at_poland77]

Does somebody has an idea, that what kind of iptables/pf rule must i use to achieve this?:

i only want to allow these connections [on the output chain]:

on port 53 output only allow udp - dns
on port 80 output only allow tcp - http
on port 443 output only allow tcp - https
on port 993 output only allow tcp - imaps
on port 465 output only allow tcp - smtps
on port 22 output only allow tcp - ssh
on port 20-21 output only allow cp - ftp
on port 989-990 output only allow tcp - ftps
on port 1194 output only allow udp - OpenVPN

So that e.g.: OpenVPN on port 443 would be blocked, because only HTTPS is allowed on port 443 outbound.

Any ideas? :\
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.ubuntu.com/archives/ubuntu-users/attachments/20110319/26c6f7ad/attachment.html>