Open ports
 

What network ports are usually open on standard Windows XP desktops and not often used for other purposes (for example, not port 80, NetBIOS, etc.)? Or at least, what ports does the Windows XP SP2 firewall not block by default?

This isn't for malicious use but a genius idea I had for a vB integrated-project (I am not modest).

ipx 213/udp #IPX over IP

Not sure if its open, but that'd be a safe bet.
Also rarely used, not many people are still using IPX...

Any TCP ports perchance for higher reliability over UDP?

UDP is fast but unreliable because there's no guarantee the packets reached their destination.

start => run => cmd => netstart -a

Can tell you what your using

http://support.microsoft.com/default.aspx?kbid=875357

Ah yes.. silly me.

Most TCP ports are used more often I was only suggesting that one as no one uses ipx and it should be open.

Given there are 65,535 possible ports, knowing what's in use is a process of elimination. :)

Hint: obviously I'm trying to make a forum talk back to its user on command using a publish-subscribe mechanism, unlike HTTP which is request-response.