The Microsoft "RTC" products (including Windows Messenger) use the standard SIP protocol for audio and video sessions. These clients use the proprietary SIP protocol extensions for Instant Messaging, Presence, Whiteboard, Remote Assistance and other services. CommuniGate Pro implements the extensions required to support these applications.
The Windows Messenger versions prior to 5.0 are not supported.
The CommuniGate Pro SIP module should have the Advertise NTLM option enabled.
The Windows Messenger audio and video sessions use standard RTP media protocols and these sessions can be used over a NAT/Firewall. The Windows Messenger Instant Messaging uses the SIP protocol for media transfer and Instant Messaging sessions can be used over a NAT/Firewall. The Windows Messenger Whiteboard, Application Sharing, and Remote Assistance sessions use T.120 and non-standard protocols and these sessions can be used over a NAT/Firewall. The Windows Messenger File Transfer sessions use a non-standard protocol and these sessions currently cannot be used over a NAT/Firewall.