Many Messenger-related protocols are called using invitations. For a discussion of the invitation protocol itself, click here. This page describes the values of fields needed to negotiate specific protocols. For protocols that require you to send "IP-Address: IP:port" instead of just "IP-Address: IP", the description will specify an "IP-Address port".

Submitting Invitation Types

If you have information on an invitation type that is not on this page, please submit it to us. Currently, we do not have a nice system for submitting invitation types. Until one is setup, please submit your entry as a reply to the forum thread Submit All Known Invitation Types (thread ID 4042).

Application Sharing

Application Sharing is some kind of SOAP-over-HTTP application we don't understand. For some reason known only to Microsoft, an IP address without a port is sent in the first ACCEPT message, then the same IP address is sent in the Context message, this time with a port.

Application-GUID: {F1B1920C-6A3C-4ce7-B18C-AFAB305FD03D}
Application-URL: http://www.microsoft.com
Context Context-Data: IP address and port for the other computer to connect to. Only 10337 has been observed for the port number

Baldur's Gate 2

Baldur's Gate 2 (which is misspelled as "Baulder's Gate2" in the official client's Application-Name) is a roleplaying game from Interplay Entertainment. The port is not specified in the "IP-Address" field, but it is always TCP port 47624.

Application-GUID: {8DAE4336-2B71-11D4-9A6C-006067325E47}

MechWarrior Mercenaries

MechWarrior Mercenaries is an FPS game from Microsoft.

Application-GUID: {41FD0FA-2942-4DC4-B4C5-73D2C55F4C94}

NetMeeting

MS NetMeeting is a voice-chat and shared whiteboard program from Microsoft. NetMeeting uses the H.323 and T.120 standards, so (despite the name) you can use any program which conforms to these standards. For example, GnomeMeeting and ohphone support H.323.

The Rendezvous Protocol specification hints at "NetMeeting 3.01", which has a different GUID, but seems otherwise identical.

Application-GUID: {44BBA842-CC51-11CF-AAFA-00AA00B6015C}

Remote Assistance

Windows XP allows you to request "Remote Assistance" from through the official client. The protocol used by XP's remote assistance package is RDP 5.1. At the time of writing, no independent implementations of this protocol were known, but the RDesktop project are apparently working on it. The various context data sent in a remote-assistance invitation are not yet properly understood. Remote Assistance was discussed in this phorum thread, but hasn't been fully deciphered.

Application-GUID: {56b994a7-380f-410b-9985-c809d78c1bdc}
Application-URL: http://www.microsoft.com
Context Context-Data: A long string we haven't been able to decipher.

Voice and video conversation

"Voice conversation" and "video conversation" negotiate an SIP (Session Initiation Protocol) session. The official client uses a built-in SIP program, but any SIP-capable program (such as LinPhone) will do. SIP is defined in RFC 3261. The audio capability is referred to as "SIP_A", while the video capability is "SIP_V". See thread 6131 for a discussion of voice chat.

Application-GUID: {02D3C01F-BF30-4825-A83A-DE7AF41648AA}
INVITE Context-Data: The capabilites of the client sending the INVITE, and the capabilites requested of the other client. For an audio and video conversation, this would read "Requested:SIP_A,SIP_V,;Capabilities:SIP_A,SIP_V,;". For an audio-only conversation, this would read "Requested:SIP_A,;Capabilities:SIP_A,SIP_V,;" (if the sending client supported video conferencing as well) or "Requested:SIP_A,;Capabilities:SIP_A,;" (if the client only supported audio conferencing).
ACCEPT Context-Data: Requested capabilities of the client sending the INVITE. For an audio-only conversation, this would read "Requested:SIP_A,;". For an audio and video conversation, this would read "Requested:SIP_A,SIP_V,;"
IP-Address port: 13455, 16253, and 55039 have been observed.

Webcam

Webcam support (which is distinct from video chat) uses the "Real Time Protocol" defined in RFC 1889. The official doesn't put curly brackets around the Application GUID for webcam support.

Application-GUID: 2A23868E-B45F-401d-B8B0-1E16B774A5B7

Whiteboard

Whiteboard is some kind of SOAP-over-HTTP application we don't understand. For some reason known only to Microsoft, an IP address without a port is sent in the first ACCEPT message, then the same IP address is sent in the Context message, this time with a port.

Application-GUID: {1DF57D09-637A-4ca5-91B9-2C3EDAAF62FE}
Application-URL: http://www.microsoft.com
Context Context-Data: IP address and port (10869) for the other computer to connect to.

Jedi Knight

Two of Lucasarts' "Star Wars Jedi Knight" games (Jedi Academy and Jedi Outcast) have the same Application-GUID.

Application-GUID: {A5794C17-F586-4941-9906-9AF0F8E62283}