the pix firewall allows the secure forwarding of real time streaming protocol (rtsp) packets. rtsp is used by realaudio, realnetworks, apple quicktime 4, realplayer, and cisco ip/tv connections.

    this feature lets the firewall handle multimedia applications including cisco ip/tv connections.

    pix firewall does not yet have the ability to recognize http cloaking where an rtsp message is hidden within an http message. also, rtsp is not supported with nat.