The web management interface is laid out the same as Linksys' other WRT54G-series routers and is in large part self-explanatory. One feature I especially liked was the online Help system. In the right pane of every page is a brief description of the page, and most pages have a "More..." link that opens another window with more detailed information about the settings on that page. Figure 5 shows an example of a Help screen:

Figure 5: Help Screen Example
(click image to enlarge)

Even if you're not familiar with some of the more advanced features, the Help system explains them fairly well. 

I found the configuration tasks easy to navigate and use. The web interface makes it easy to quickly set up your network and wireless basic configurations. Once the basics are done and everything's working, then you can move on to the more advanced options like dynamic routing, IP filtering, and port forwarding if you'd like. 

If you run a server that needs to be exposed to the Internet as I do, then the firewall system can do that, but unfortunately the server will have to be on the same local network segment rather than its own. For instance, I run a web and email server, so in Figure 6 I've set up port 80 and 25 to be forwarded to that system.

Figure 6: Port Range Forwarding
(click image to enlarge)

Normally my web and email server is kept on a separate physical segment and network subnet, which I feel provides greater security in the event the server is compromised, but that isn't possible with the GP2. It does however, provide some advanced features such as Quality of Service and UPnP Forwarding that many firewall systems do not have. I'd suggest though, that you make sure you understand the security implications involved before opening any port, but especially if you're enabling UPnP Port Forwarding. See this article for more info.

The firewall and router functions of the GP2 include some other advanced tools as well, such as a Dynamic DNS updating feature, dynamic and static routing, and IP, port, and MAC filtering. Using these tools, you can configure the device to work in almost any network setting, and you can ratchet up the security to make sure that the only communications you approve go through.