So I have a strange problem and I'm not even sure how to begin trouble shooting it. I have two machines: MacA (MacMini C2D 2GHz, 10.5.2) and MacB (PB G4 1.67GHz, 10.4.11). They are on the same wired network. One IP is AA.BB.123.456 and the other is AA.BB.789.012 (they have the same sub-network? AA.BB?). They also have the same external IP, so I think each machine is on the same router within the building (this is an office setting). As the title states I can't AFP from MacA to MacB, but I can from MacB to MacA. Both have file sharing enabled. What gives?