Pour Messenger 4.6
Administrator/User Action Required
To enable voice and video communications with Windows Messenger through a non–UPnP firewall, configure the firewall to allow incoming traffic on UDP ports 5004 – 65535.
For other purposes, enable the following ports:
File Transfer: 6891 (to allow 10 simultaneous file transfers open ports 6891 through 6900)
Application and Whiteboard Sharing: 1503
Remote Assistance: 3389
http://www.microsoft.com/WindowsXP [...] #solutions
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Resolution of Censure