Does anybody know any simple user-interface program that can allow/block incoming or outgoing packets of an IP address (or UDP port) ?

For example, I want to block incoming packets of an IP address but I'll allow outgoing packets to that IP address.

As far as I know, Ghostwall can do that but it's unstable as it's not really sending any outgoing packet when I enable the 'Allow Outgoing Packets' function.

(I'm using Windows, by the way.)

Thanks in advance! And before you go *WTF*, this is not for security reasons.