Why couldn't I have conversation with my friend online through MSN messenger?

[masama]

We can chat with instant message, but why couldn't we have an audio conversation? The program always tells me that can't connect to my friend's computer, will the fire wall protection gonna disable the audio port or what?

 

[knutp]

http://www.microsoft.com/windowsxp/pro/techinfo/deployment/natfw/default.asp

I hope you will get some usefull information out of those documents.