I run a server on my comp through a Linksys on a DSL connection. I have a static IP provided by my ISP, but this does not affect my home network, DHCP works as normal.
(You will have 2 seperate IP addresses, an EXTERNAL, and an INTERNAL. The INTERNAL IP's should be 192.168.1.xxx , 192.168.1.1 being the IP of the router)
If you have DHCP active, you can still specify an IP for internal computers. (if you wish) Just right-click on Network Neighborhood and go to Properties. Next select TCP/IP, then click on the Properties button. Click Specify an IP. Then enter IP 192.168.1.xxx , Subnet 255.255.255.0
Set WINS to Disable, Set Gateway to 192.168.1.1 then click add. Click on the DNS tab, in the Host field enter the name of your computer. Add at least 2 DNS servers to the search order, usually 4.2.2.1 , 4.2.2.2 , sometimes 4.2.2.3 too. This will set up that computer as a static IP on the network. DHCP will still work normally, it will just detect a computer with that IP and automatically assign different IPs to the other comps.
(more on this later, gotta go I'm at work.

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