The TZW has some features that will be helpful to folks with more advanced networking needs. For example, if you have more than one IP address from your ISP, you can define 64 different One-to-One NAT groups. Each definition assigns a range of private LAN IP addresses to one of the WAN IP addresses. This would let you, for instance, set up two different web servers, both running on Port 80, but answering to different WAN IP addresses or domains.
You can also establish Static Routes to handle networks with more than one subnet and flush and set the cache timeout for the TZW's ARP table. But if dynamic routing is your thing, the TZW unfortunately doesn't give you any control over the handling of RIP or other dynamic routing protocols.
If you have a proxy server on your network, you can move the server to the WAN and enable the Web Proxy Forwarding feature. The TZW then automatically forwards all Web proxy requests to the proxy server without requiring you to change the proxy settings on every machine on your network... a royal pain if you've ever had to do it!
I previously mentioned that there are separate DHCP servers for the LAN and WLAN segments. But I neglected to say that you can set the address ranges, and also program specific IP info by MAC address, including segment type, gateway and DNS and WINS server info.
You also get a number of diagnostic tools including the ability to Ping, run traceroute, do a hostname (or reverse) lookup, and run a packet trace on inbound traffic.
I could go on, but it's time to move on to Performance.