Go to System Preferences. Select the Network tab. In the Configure menu, select Advanced. Create a new interface by clicking on New... and select Built-in ethernet. Name it what you want, I recommend Cluster.
Now select Cluster in the Configure pop-up menu and then the TCP/IP tab. Enter the following: IP Address: 192.168.0.1 Subnet 255.255.0.0 and router 192.168.0.1. You cannot enter any address you want: you must enter a legal internal adress (see this for details if you really want to know).
|Legal address range||Subnet mask||Recommended address|
|192.168.0.0 to 192.168.255.255||255.255.0.0||192.168.0.1|
|172.16.0.0 to 172.31.255.255||255.255.240.0||172.16.0.1|
|10.0.0.0 to 10.255.255.255||255.255.255.0||10.0.0.1|
Then go to Appletalk and activate it. Save and exit.