Welllll,
Mac's using appletalk do not use the physical(MAC) address of the nic
installed in them. Appletalk advertises a software originated physical
address to see if it is in use. If not, that's the physical address assigned
to the node. This physical address is not ethernet compliant. So as long
as you use a hub, which doesn't care about the physical address, you're
fine. In a switched environment, the switch memorizes the ethernet
physical address of each node on it's ports. The Appletalk physical address
is not recognized so the switch does not know where to forward the
packet.
Change to Apple's TCP/IP, problem solved. Newer the version, the better.
Dennis