Security

Ask something
Discussion Locked

Blocking Instant Messaging- my wits end!

0 helpful
5 replies

by tty35

Closed to new repliesThis discussion is closed. It stays readable, but it takes no new replies.

I'm trying to find out how other Admins. go about blocking the numerous Instant Messaging Applications out on the Net (Yahoo IM, ICQ, etc..) from being use on their LANS. I used to combat this menace by blocking the various IP's to the Messaging Servers, but this is just a temporary solution as the providers just change their DNS settings for these servers to point to a new IP and then the services goes right past the Firewall. And blocking specific ports is no help as these applications now scan for available Outbound ports and use what's is open (i.e., http, ftp, etc..). So I'm trying to find out ways others have found to address this problem.

Any help would be much appreciated!

5 replies

by admin

Regular software audit network scans and an approved software list. If it's not on the list and and\or installed by an unauthorized person, delete it and check to see who installed it, then begin the appropriate discipline process. If your company needs instant messaging then keep it uniform with one client and monitor it.

by melvine

We use the Packeteer to block anything we want. Regular ACL's blocking ports don't seem to do it anymore as these Instant Messaging Applications jump from one port to another. However, the Packeteer filters based on the application layer rather thantransport or network layer.

by raif

We also use Packteer on our network, ,and tell it to drop AOL-IM. It doesn't work.

by brian patow

If you have a firewall you should be blocking ALL ports. You should only allow out traffic for which you have a rule for. You would be amazed at what apps you will find in use when you block ALL ports. Once you do this make sure there is a good business reason for adding rules (opening up a port) and allowing out traffic out/in.

This discussion is closed to new replies.