With MacTCP set to do dynamic addressing, the user fills in the Network portion of the IP address. A Macintosh computer configured in this way dynamically assigns itself an IP node address based on this network address, and tests to see if this address is in use. If the address is not being used, MacTCP uses it, and does not release it until the computer is shut down.
MacTCP also supports server-based addressing through either Ethernet (bootp), or AppleTalk (DDP/IP). An unsuspecting user might configure both dynamic addressing, and bootp or DDP/IP addressing with the result that the Macintosh computers will assign themselves node IDs in the network range entered in MacTCP, but never consult the bootp or DDP/IP server.
The correct setting in MacTCP for server-based addressing is server, not dynamic. Server addressing through AppleTalk is either EtherTalk, LocalTalk, or Apple Remote Access; while dynamic addressing means independent arbitration.