Block Internet Messenger With Iptables

normally we will use port filtering with iptables to block the internal user from accessing unwanted application or website but here the tips for you to do it :


If you’re a network administrator and you’re using Linux on your servers, you can stop the rest of the users from using IM applications by blocking their access to the most-used IM protocols:




ICQ and AOL:


# iptables -A FORWARD –dport 5190 -j DROP
# iptables -A FORWARD -d login.oscar.aol.com -j DROP


MSN:


# iptables -A FORWARD -p TCP –dport 1863 -j DROP
# iptables -A FORWARD -d 64.4.13.0/24 -j DROP


Yahoo Messenger:


# iptables -A FORWARD -p TCP –dport 5000:5010 -j REJECT
# iptables -A FORWARD -d cs.yahoo.com -j REJECT
# iptables -A FORWARD -b scsa.yahoo.com -j REJECT