I've just installed OS X Leopard (10.5) on an old Power Mac G5 (Dual 2 GHz) : everything went well but impossible to connect to my local network using ethernet cable.
I've test the cable : working perfectly on my MacBook Pro, as well as with another iMac G4 (also with Leopard).
Tried to restart the router, but no way : in system preferences, I still have 'Network cable is unplugged' ... )
Any help kindly appreciated !!