The Apple Airport networks document says that fixed IP addresses should be in the following ranges: 10.0.1.2 to 10.0.1.200 172.16.1.2 to 172.16.1.200 192.168.1.2 to 192.168.1.200 Is adhereing to the above ranges a necessity? I've added an MBP and Time Capsule to my previous all PC network. The TC is replacing an older Linksys WiFi router. My fixed IP addresses are in the range of 192.168.2.100 to 192.168.2.250. The above .200 addresses are easy to change, but changing 192.168.2.xxx to 192.168.1.xxx would be a bit time consuming and would have to be done in the proper sequence, so I want to be sure it's needed. Via LAN and WiFi, internet access is okay, pinging works in all directions, my two LAN printers work, but file sharing and Mac to PC/PC to Mac access rarely works. Even forcing connections through Finder is iffy, at best. All network and sharing settings are set up properly. The only thing left is this apparent IP address restriction, but is it really an issue? UPDATE: After days of frustration with this, I finally changed my entire network to conform the default Time Caspsule IP address of 10.0.1.1, and subsequent range of 10.0.1.2 to 10.0.1.200. The result is that the share problems are resolved, and the wired LAN is solid. So, my experience is that Apple's recommended IP address ranges should be used.