Appendix Network Connection
© Polycom, Inc. 67 ViaVideo User’s Guide
automatically discovers your external IP address and enters it in
the NAT Outside (WAN) Address field.
If you are using a proxy server, the Auto discover NAT IP
Address option may not work correctly. You should enter your
NAT’s external IP address manually in this case.
Open and Assign Ports in the Firewall
To configure your ViaVideo to operate with a firewall, perform the
following tasks.

Before you Begin

Before you start, determine the internal IP address of the PC running
ViaVideo. To do so, start the ViaVideo application and look in the
System Information screen.

In Your Firewall

You will need to open and assign ports to the PC running ViaVideo
in your router’s firewall interface software. The exact steps and
terms involved are probably different in your firewall interface.
For example, opening and assigning ports to the PC running
ViaVideo is referred to in the Linksys firewall interface software as
“Forwarding,” while the Cisco firewall software refers to assigning
ports as “Port to Application Mapping.” However your firewall
interface describes it, the concepts and tasks remain the same.
1. Open a range of ports in your firewall. We recommend that you
open the default ports: 3230-3235 for TCP and UDP.
2. Open port 1720 in your firewall. You must open this port for your
ViaVideo to receive incoming calls.
3. Assign the port range to the PC running ViaVideo.
In some firewall interfaces, opening and assigning port numbers
is performed in one step.
In some firewall interfaces, you assign the ports to an IP
address, while in others you assign the ports to an applic ation,
in this case ViaVideo. Either way works fine.

In ViaVideo

Now you need to point ViaVideo at the right port numbers.
ViaVideoUG.book Page 67 Thursday, December 7, 2000 2:49 PM