This is a port of Apple Computer's open source rtsp_proxy.

QuickTime streaming uses RTP/RTSP protocols

Recommendations for Firewall Administrators:
QuickTime follows the conventions of the RTP and RTSP internet standards
to stream media over the web. To enable QuickTime 4 to work properly
inside your firewall, please follow the following IETF recommendation: 

- Open port 554 for RTSP/TCP data.
- Open ports 6970 through 6999 (inclusive) for RTP/UDP data.

For more information on the RTP and RTSP internet standards:
- RTSP: http://info.internet.isi.edu:80/in-notes/rfc/files/rfc2326.txt 
- RTP: http://info.internet.isi.edu:80/in-notes/rfc/files/rfc1889.txt 

WWW: http://www.apple.com/quicktime/developers/rtsproxy.html