As the owner of a small network, ie 3 computers, at home, i dont know that much. What i do know is, you can set a TCP/IP address or have the machine automatically(DHCP) get one fram the server(WIN98 SE). If you check ( your client,ie win 98)you will find in the settings that you have it set to find one, change this to manual setting and give it one,this will be you static address and will not change. As regards one machine can see the other, this is the client, the server will not see the client, i simply put any files on my client that i want to see on the server in the shared file of the server, and thus can see all files i want on both machines.
I Would tell you more but im a bit dodgy on this issue, but havin fun trying to figure it out!!