Grab your Partner!
Since I'd heard so much about how a WinXP computer and a UPnP enabled router were supposed to find each other no matter how the XP client was set up and without requiring any reboots, I thought I'd poke at that first.
I took my trusty, but aging, Compaq 1650 laptop, that I'd recently loaded with WinXP Home and that was happily connected to my SMC7008 main router (and the Internet) via a Linksys PCM100H1 HomeLink Phoneline + 10/100 Network PC card (yes, that's a strange choice, but my trusty generic 10Mbps PC card Ethernet NIC died during my experiments). WinXP had installed the NIC, using the latest drivers downloaded from Linksys, and configured it with the default assortment of services as shown in Figure 1 below.
XP had set the NIC to "Obtain an IP address automatically", and the adapter had successfully leased IP address information from the SMC router in the 192.168.3.XXX subnet and was added to the the Network Connections window as shown in Figure 2 below.
Tip: You must have the TCP/IP protocol installed, set to "Obtain an IP address automatically", and no Gateway or DNS information entered in the TCP/IP properties. This is the default setting for WinXP, but not for earlier OSes.
If you manually set your IP address or other TCP/IP properties, UPnP will not override those settings and may not automatically connect to your UPnP-enabled router.
So far, though, no UPnP magic had been invoked because the SMC7008 is not UPnP enabled. So I left the Network Connections window open, unplugged the Compaq's Ethernet cable from the SMC, plugged it into the D-Link DI-804, and waited to be amazed. After about 10 seconds or so, the Network Connections window began morphing and after about half a minute had changed to what you see in Figure 3.
The Linksys was slower to appear in the Network Connections window, taking about a minute to finish its configuration.
Hmmm... a new icon. Let's go check it out!