NW Doc

For Windows Vista & Windows 7 above

This is easy using the 'netsh' command.

To block it we would call it like this:

netsh advfirewall firewall add rule name="BlockAIM" protocol=TCP
dir=out remoteport=4099 action=block

Let me explain each setting:

name = The name of the rule. (Pick something descriptive)
protocol = The protocol we are going to block (UDP or TCP for most cases)
dir = The direction of the block. Can be IN or OUT
remoteport = The port of the remote host that is going to be blocked
action = Could be block or allow. In our case we want to block the connection

Once you execute the above code, all outbound requests to any host on port 4099 will be blocked, and it adds an entry to the Windows firewall.

If you want to remove the rule from the command line, you can call netsh like this:

netsh advfirewall firewall delete rule name="BlockAIM"

That is all there is to it. One line to add a rule, and one line to remove.