The usual is a firewall which I feel the firewall maker deserves that feedback...
http://www.ntu.edu.sg/CITS/Getting+Help/get+me+connected/im+quick+start+guide.htm notes the firewall issue, but doesn't detail what ports to open. Your firewall supplier should reveal this.
Bob
I am using Windows XP Pro service pack 2 and Yahoo Messenger. I set my status to "available". None of my friends who use it can see me as online, or available even though I signed on and set my status as available. My internet service is Verizon DSL. Do I need to do something with my Yahoo settings to make it work ? Windows XP firewall is also enabled. Yahoo's tech support is non existent, sending them an e-mail is useless and I only get general statements about it being a temporary problem....

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