Audio and video do not work when you connect to a Live meeting 2007 session through an authenticating proxy server

You find that audio and video do not work when you connect to a Microsoft Office Live Meeting 2007 session through an authenticating proxy server.

To resolve this issue, you must disable proxy authentication for the following range of IP addresses so that user authentication is not required for the Live Meeting 2007 service:

• 64.41.193.0 /24
• 216.34.51.0/24
• 204.176.46.0 /24
• 65.221.5.0/24
• 94.245.113.0/24
• 204.79.179.0 /24
• 216.32.242.0/24

When you use audio and video in a Live Meeting 2007 session, Live Meeting 2007 uses one of the following methods:

• Live Meeting 2007 uses a direct connection to a media relay.
• Live Meeting 2007 uses the proxy settings that are configured in Windows Internet Explorer to connect through an HTTP proxy connection.

The following two protocols are used for audio and for video in Live Meeting 2007:

• User Datagram Protocol (UDP) port 3478
• Transmission Control Protocol (TCP) port 443

Typically, UDP is preferred for performance. However, UDP connections can cause network congestion. Audio and video use TCP if UDP ports are blocked. TCP lowers network congestion. However, TCP also lowers the quality of audio and of video. Audio is affected the most when TCP is used because the ear is more sensitive to disturbances. When you use TCP, audio and video are encrypted by using Secure-RTP. To decrypt the audio and video media, Session Initiation Protocol (SIP) signaling is performed through SSL port 443.

When you connect to Live Meeting Manager, SSL port 443 is used. This is a Web site where meetings can be scheduled and updated over the Internet.

To enable users to watch streaming recordings of a video or to hear streaming recordings of audio, the following range of streaming ports is used:

• TCP ports 80, 443, 554, 1755, 7070
• UDP ports 1755 and 5055

If these ports are not opened, users can still download a recording over SSL port 443.