From XP-SP2. the firewall setting default will block all app connection except user approval. So, you can approve every app you want to execute and let it work correctly under XP-SP2 (also in Vista).

But if your appllication is a Window Services? How it work under Microsoft firewall ?

It will be blocked the communication automatically!!

Yes, ~~  if your app is a P2P window services, you will find it doesn’t work when the service is work, even you never get a assert dialog box.


How do workaround with firewall, if my application is a Window Service?

Use “Netsh” to change your firewall setting. For example if you want to enable specific app “fooAPP.exe”.

netsh firewall add allowedprogram “c:fooAPPfooAPP.exe” fooAPP ENABLE

if you want to disable a APP from firewall.

netsh firewall delete allowedprogram “c:fooAPPfooAPP.exe”


Attitude is everything