The Battle of the Services!
Updated 8/2/02 While gathering data for this article's update, I decided to check out how well changes in Service settings (manual port mappings) were coodinated between UPnP and a router's normal admin interface. Since I'd found the D-Link DI-804 to have the best UPnP implementation so far, I chose it as my guinea pig.
Tip: I first upgraded the 804 with 4.68 firmware, which turned it into the DI-804U, according to the new admin screen! I also found out that you'll need to check that your version of Windows Messenger is 4.6.X. I found this out when my new Dell 4100 laptop didn't appear to be activating NAT Traversal for Messenger. Turned out that the Dell had come with the older 4.0 version of Messenger, which apparently doesn't have the NAT Traversal feature baked in.
I found that a service added via the DI-804's UPnP interface did not show up on the 804's internal browser-based admin interface Virtual Server Settings page. The 804 did, however, properly establish the requested service and open the required ports, which I confirmed by port scanning the router. It also properly closed the ports when I removed the service via the UPnP Services interface. Another pleasant surprise was that the 804 didn't have to be rebooted to add or delete the service, as it does when you change a Virtual Server setting via its normal Admin interface.
Similarly, a virtual server programmed on the 804's admin interface did not show up in the UPnP Advanced Settings > Services. The required ports were again properly opened, however.
I next tried to add the same service via both methods. I found that I was able to add the same exact port mapping on both interfaces (same ports, same LAN IP) and did not get any warnings or complaints from UPnP or the 804. I was also able to remove or disable the port mapping from each interface, but the ports were not closed on the router until the mapping (service) was removed via both interfaces .
The bottom line is that, at least for the DI-804, UPnP and the 804's browser admin interface don't communicate with each other about port forwarding (services).
Tip: My advice here is pick an interface, either the UPNP Advanced Settings > Services interface, or your router's admin screens if you're going to open ports in your router's firewall. Although it's nice that you can open ports using both methods, the ports won't be closed until you close or delete the mapping from the interface you used to open them with! If you forget that you opened a port with one interface, and then open it with the other, you'll need to remember to go back and remove the mappings with both interfaces to close the ports.