on the first,, yes you could install a DHCP service on the Win2k server, this would be done with the add/remove OS option in add/remove programs in control panel, now if you do enable this option, you are able to set an active scope of addresses,, say for instance 192.168.0.1 - 192.168.0.254 (or smaller)x.x.x.100?
I dont have a win2k server in front of me right now, but on it , in the administrative tools there is a Microsoft Management Console option, in there you are able to config most things,,
As for the Internet Connection sharing, this is not like win98, using a multihomed server, you are, essentially, making the server a router, using the first NIC as your gateway... so no you do not NEED to enable ICS
You will however, either have to make the server provide IP forwarding, or have the users "logon" to the win2k server for an IP address, and Internet access, this is good if you want to apply permissions to accounts etc..
To clarify, I am thinking that you have a home LAN, and a win2k server setup to share the Internet(WAN) connection?
On the TCP/IP thing, yes, like anything an IP address is like your House Address, and your Postal Code, in order for computers to "see" each other , they have to be in the same neighbourhood, hence "network Neighbourhood"
So if your house number is "7" = "192.168.0.1" and your postal code is "N1G 6S9" = 255.255.0.0 and to get out of your neighbourhood to another neighbourhood you need to travel on "Highway 401" = gateway
Your neigbour would be "9" = 192.168.0.2 with the same postal code "N1G 6S9" = 255.255.0.0 and he/she uses the "401" as the highway too, then yes they will see each other.
For sharing files, you will have to go into the network properties and either add file and print sharing to the machines, or enable file and print sharing on the machines, after a reboot, you will have the option from a right click to share files and to whom,,,
This really is an entire course to understand the whole concept completely,,
hope this helps somewhat,,,
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