802.11g -> wired ethernet bridging not working

Question

Usually people want to go the other direction, but I want to take our relatively fast and stable house 802.11g signal and bridge it to ethernet. I have tried using an Airport Express (the b/g flavor) and my i7 MacBook pro, both to no avail. Word is that the b/g flavor of

This flavor of Airport Express maxes at firmware 6.3 which doesn't support this kind of bridging properly. However, I expected my MacBook pro to do the job with its "Internet Sharing" feature. Alas, although my wired PC does sort of see it, it doesn't work out. Strangely, using DHCP the PC receives the same IP address as my MBP uses on the network. Less strangely, but still surprisingly, the wired ethernet port on my mac registers as the IP address of the gateway when queried with IFCONFIG.

It sort of makes sense that the mac would "pretend" to be the gateway, but the whole thing just isn't working and seems configured wrong - but all the docs I see say basically "OS X Internet Sharing: click it and go".

What do I do? Do i really have to buy more hardware, even though I have plenty of would-be candidates for bridging?

Incidentally, the host router originating the 802.11g signal is a belkin 802.11g router, and is documented to support WDS.

Answer 1

The b/g AirPort Express does indeed support WDS wireless bridging, but Apple never officially supported WDS interop with third-party 802.11 gear. You might still be able to get it going, but beware that WDS requires a fair bit of manual setup:
How to create WDS wireless link between two home wireless routers?

If you want to go with the MacBook Pro situation, beware that since the MacBook Pro doesn't do bridging, you'd end up doing double NAT, which most network designers strive to avoid.

I believe Mac OS X's Internet Sharing may hard-code its NAT private address range to 10.0.2.x. If your upstream NAT gateway is set to use that range right now, but lets you change it, then change the upstream NAT gateway's private address range so it doesn't conflict with the one Mac OS X's Internet Sharing NAT feature uses.

Because the Mac will be acting as a NAT gateway and DHCP server (just on the Ethernet side, serving the PC), it's right for the PC to receive a configuration via DHCP that says it should use the Mac's NAT private (Ethernet-side) IP address as the PC's default gateway address.