Aqyi estão as regras para o MSN:
ip firewall mangle
add chain=forward out-interface=pppoe-out1 protocol=tcp dst-port=!1863 \
tcp-flags=syn action=change-mss new-mss=1492 comment="MSN" disabled=no
add chain=forward out-interface=pppoe-out1 protocol=tcp dst-port=!5190 \
tcp-flags=syn action=change-mss new-mss=1492 comment="" disabled=no