I'm not a mac user but I'm pretty good with networking. If you mac already share the net out to the other ones can't you just crossover a cable to the Amiga and direct connect. If you don't have one you can take a standard net cable and make it a cross over like this
Pins
1----3
2----6
3----1
4----4
5----5
6----2
7----7
8----8
Should make a crossover for ya 1 to 3 and 2 ta 6 the rest aren't really even used for anything else other than a cleaner connect. Makes it go faster if you know much about Twisted Pair.
Hope that helps.
