Blocking ports

Does anyone know which ports to block to prevent users from using chat
/ IRC groups use, like Yahoo, MSN Messenger and Windows Messenger?

Thanks!

Nell

Nell <> wrote in
news::

> Does anyone know which ports to block to prevent users from
> using chat / IRC groups use, like Yahoo, MSN Messenger and
> Windows Messenger?

This help?

http://www.chebucto.ns.ca/~rakerman/port-table.html

Jim

Jim

If you do a Google search for MSN messenger ports etc you will find the
information OR do a little detective work on a computer that is running
them. You can use the command netstat -an to see what ports a computer is
using or better yet use a free tool like TCPView from SysInternals to see
the port use. If your firewall has the capability it is best to start with a
default deny all rule for outbound access and then define the authorized
exceptions. Also keep in mind that a lot of chat programs will attempt to
tunnel through port 80 TCP which is used for internet http and can make it
difficult to stop unless you can find and block the IP addresses of the
servers they tunnel to, use software firewalls that have application based
rules like Zone Alarm, Sygate, Norton, etc. or use a gateway firewall device
that can do advanced application filtering for http like Microsoft ISA
004. --- Steve

http://www.sysinternals.com/Utilities/TcpView.html


"Nell" <> wrote in message
news:...
> Does anyone know which ports to block to prevent users from using chat
> / IRC groups use, like Yahoo, MSN Messenger and Windows Messenger?
>
> Thanks!

Steven L Umbach