Why would you ever want to plug one router into another router?
To add more NIC ports? NO, use a hub.
To get more addresses? YES, in very, very rare circumstances.
But you'd have to have thousands upon thousands of local computers on the local network to warrant adding a second router and it's subsequent additional NAT overhead.
NAT (Network Address Translation) is not free. It adds overhead to the TCP/IP protocol making packets headers longer than necessary. The Gateway is already a router and a NAT Firewall. There is no need to use a second device between your web server and the public internet.
Using the SMC Gateway Cable Modem you don't need a second router to serve pages to the internet and you don't need a separate router for other computers on the Gateway to use the internet. You can use the existing public IP of the gateway as long as you don't have any other service running on port 80 (web browsing is not a service, a web server is a service. NTP is a service, FTP is a service, SMTP is a service, POP3 is a service, IMAP is a service.). If you want to set up a second web server (Why???) plug it into the gateway, assign it a unique subnet IP (10.1.1.101) and use one of your other public IP addresses. Then forward port 80 for the second IP to the second web server. Using the SMC Gateway you can easily run four concurrent web servers. But again, why would you want to do such a thing? Even the fastest Comcast connection can be easily saturated by a moderate P4 or newer home computer running Apache2 or even IIS. And let's not forget torrents or emule.
First off I suggest you not use any version of IIS for web serving. Even Microsoft uses Apache2 for a web server on some of their sites that don't require MS specific services because it's just plain faster. IIS requires twice the RAM as Apache2 and its still slower. Apache2 runs under Unix, Linux, OS/X, PPC, and Windows on Sparc, Sun, Intel and AMD hardware and probably others so there is no reason to even install IIS. Plus, Apache2 is nearly free. (Do make a donation if you use it!) My home server runs Apache2 and uses a whopping 200-+ Meg of RAM on a 2Gig system. The remainder of the RAM is for disk cache. You need enough RAM in a web server so it almost never swaps. Swapping is the bane of any web server. Many Admins turn swapping off if they are confident the server will never need it. Mine can run for weeks without a single byte written to the swap file. If I see any swapping activity I check my logs. It usually means my configuration is messed up.
SMC Gateway Web Server; It's this easy:
- Plug the web server computer directly into the gateway.
- Configure it with a static IP on the same subnet as the gateway's DHCP server. Just make sure it's outside the DHCP range or you might end up with duplicate IP warnings and network failures/Gateway lockups. If the DHCP range is 10.1.1.10 to 10.1.1.50, 10.1.1.100 would be an appropriate address for your web server. Do make sure it's on the same subnet. Don't use 10.2.1.xx or 10.1.2.xx you'll have communication issues.
- Always use 255.255.255.0 for the netmask everywhere unless you know EXACTLY what you are doing.
- Set the DNS address of the server to the SMC Gateway IP (10.1.1.1) or whatever it is.
- Set the Gateway address of the server to the SAME IP as the DNS above. In this case the Gateway serves as both your DNS and internet Gateway because it's acting like a computer itself. All data is passed between the gateway and the public IP. That's why it's called a Gateway.
Alternatively you can look in the Gateway setup and set the DNS and Gateway addresses on the server to the values from the Gateway's public IP but it's unnecessary and one more thing to remember if you move the thing.
- Navigate to your Gateway administration page in a browser and forward port 80 to the static IP of the web server. It's that simple.
- Adding a second "gateway" or "router" between an existing gateway or router and your server makes it nearly impossible to debug communication issues. It also adds significantly to the TCP/IP packet header (sent with every 1500 bytes of data) and forces you to change port forwarding in up to three different devices if you want to make changes to your ports.
- Keep it simple. Read up on IP addressing schemes and make sure you know the difference between DHCP and DNS.
If you are forwarding port 80 through a router you can disable the firewall on the server.
- There are two private network address ranges that are forbidden or ignored on the internet.
192.168.x.x - 192.168.255.255 (65,536 addresses) is intended for personal home computers and small local networks.
10.0.0.0 - 10.255.255.255 (1,048,576 addresses) is intended for campus sized networks for large corporations and educational institutions.
Lastly you can read some of my experiences with Debian/Apache2 here:
I currently run a home server at trbailey.net using a DSL modem and a web server. In my case the server acts as the "Gateway". No separate router, no hardware "Gateway". I ran across this post looking for experience setting up the Comcast Gateway I'll soon be using.