One thing that is necessary when dealing with IP videoconferencing is the whole network management thing. This means dealing with DNS, ports, and firewalls.
DNS remains a bit of a mystery, but in essence, the DNS system maps numerical IP addresses to domain names. So for example, my web site is located at 220.127.116.11. The way I know this is by running the NSLOOKUP command in Windows.
You can find your current public IP address by going to www.whatismyip.com
For help in setting up your router with port forwarding, go to http://portforward.com/
Laura Chappell produces fantastic tutorials on network troubleshooting. I should say “still”…because I’ve been reading her stuff since Novell was the networking operating system, and that is going back close to twenty years. The linked tutorial, from Novell Connection Magazine is entitled 10 Tasks Every Troubleshooter Should Conquer.
She references the SecTools site for tons of networking tools