How to turn a port XP

You cannot specifically block a port on most systems without using a firewall of some sort. Fortunately, XP has one built into it. If you have already enabled it then all ports are blocked except what you specifically allow. If you have not then take a look at the instructions below to enable the firewall.

Select Start | Connect To | Show All Connections.
Right click on the network adapter that you want to secure.
Select Properties
Select the Advanced tab
Check the ?Protect my computer?? box.
Click the Settings? button in the lower right corner and configure away.

You can also use the IPSEC configuration on the located on the Options tab under Advanced properties of the TCP/IP settings on the adapter. This will allow you to specifically block and allow ports. Using both of these techniques can be quite flexible and very secure.