Why do I care DMZ or port forwarding?

ADSL router has simple NAT/firewall built-in. It blocks the connections initiated from the public Internet. If you place an IPX behind an ADSL router, by the default the voice calls from the Internet would not be allowed to come through the ADSL router. Since the IPX is actually a voice application server, to receive calls from outside user needs to set DMZ or port forwarding on the ADSL router. "Howto work with Firewall" has some information about IPX to traverse firewall.

Concept of DMZ and Port Forwarding

Port Forwarding: Network application is identified by the TCP or UDP port. Port forwarding is a rule configured on ADSL router such as: if the connection from the public Internet comes to the ADSL router at port 8080, the connection is forwarded to the host 192.168.1.100 at the same port 8080. In this way, the application server defined on 192.168.1.100:8080 will be able to serve the requests from the public Internet.

DMZ: A DMZ allows the IPX on your LAN to expose to the Internet. In theory, the IPX is no longer 'behind' the firewall.

Port Forwarding vs DMZ: A DMZ is far easier to set up than port forwarding. If DMZ is already setup for another host, you will have to setup port forwarding for IPX. When both port forwarding and DMZ is configured, the port forwarding is used first, then the DMZ setting.

http://portforwarding.com/ has complete and detail information on port forwarding setup for most available ADSL routers.

Ports used by IPX

The default ports used by the IPX systems are:
TCP: 8080
UDP: 8060, 8086, 8087, 8088, 20000, 20001, ..... 20015

The some port numbers are modified in the IPX management page, the port forwarding entries would need to be differently as well. When port 8080 is blocked by local ISP, you can do a port mapping from 8888 to 8080. In this case, you can remotely manage the IPX using http://xxx.myIPX.net:8888/