MikroTik

hi guys
i need to close p2p programs
most my users only browseing the internet and using yahoo messenger
i want to close all ports Except 80 and (yahoo messenger port)
i need to know if this will Cause problem in MT and for users
thanz

Perhaps close all ports then open common ones

20,21, 22 25, 80, 110, 443

You will get a few phone calls and need to open more ports

Otherwise use firewall, its can drop most? p2p traffic built in

53 port number is required for DNS serivce, it is also very important service.
Most popular p2p protocols are recognized by the MirkoTik RouterOS,
you can use '/ip firewall filter add chain=forward action=drop p2p=all-p2p'.