When ISA server is installed on a Windows 2000 server that is running NetMeeting, NetMeeting does NOT accept incoming calls.
This behavior occurs because ISA server and NetMeeting both use port 1710.
NOTE: ISA server is unaffected by this behavior. It operates normally.
NOTE: Only NetMeeting on the ISA server computer is affected. NetMeeting on the ISA server computer can initiate outgoing calls. Clients can use NetMeeting via the ISA server without any problems.