Hi,
There are a couple of approaches you can take configuring your Local Area Networks IP Addresses, below is my suggested way which should teach you a little bit about the concepts we are working with. Some casual considerations that need to be made are:
1. How large your network is
2. Whether you have friends with laptops/pcs who come around and want to plug into your network and connect to the internet without any manual configurations
3. How well you know the concepts of networking.
Now based off your post, we should begin with considering point no. 3. And I also presume when you say "Local" you mean the Windows 2000 machine running WinGate, and the LAN as the clients that will connect to WinGate to share the internet connection.
Windows 2000 machine running WinGate
External IP address ... internal modem or external router? If it is already working, no changes should be required.
Internal IP address 10.0.1.1 (Network card facing the internal network)
Subnet 255.255.255.0
Client machines to share the internet connection from Win2000 WinGate server
IP address 10.0.1.x where x is any number between 2 and 254
Subnet 255.255.255.0
DNS 10.0.1.1
GATEWAY 10.0.1.1
On the client machines, the DNS is used to turn domain names to ip addresses, e.g
www.google.com = 64.233.187.99 ... The DNS is set to 10.0.1.1 because the WinGate server performs that service.
Also on the client machines, the GATEWAY is used when an IP address cannot be found on the local network.. So on the client machine when they put
www.google.com into internet explorer, DNS will return the IP address of 64.233.187.99 , and your computer will say to it self, "Well 64.233.187.99 is not on my local network, so I will send it to the GATEWAY to find it". WinGate is the GATEWAY and will track down the location to get the Google web page from.
Once you have the Manual IP addresses concept sorted out. Then you can change it to use DHCP (automatically allocating IP address.) and have more automation over your network.