[Hudlug] Videoconferencing

[Tim Bray]

Anne Wilson wrote:
> Has anyone tried video conferencing through a firewall?

This is my job.

Do you want to explain a bit more?

I am presuming that when you say firewall, you actually mean NAT.

But basically the problem goes like this.  H.323 conferencing (gnome 
meeting, netmeeting, ProVU IP videophone) uses UDP to send the audio and 
video.  UDP is not connection oriented, and so the NAT has a hard time.

But usually you can get it to work by using using port forwarding, and 
also telling the video conferencing software/hardware what it's external 
IP address.

The H.323 standard says that all UDP ports from 1024 upwards must be 
open.  In reality most software uses specific ports, so you know which 
ones to open/forward.

Ideally, get an ISP who will give you some IP addresses.

Tim