Using a Mac as a wireless access point

Question

I am trying to setup a Mac as a wireless access point to an existing network. Internet is shared from the Ethernet connection to AirPort, and AirPort is all setup. I can connect to it with a wireless device. However, when I try to access something on the Ethernet side of the network, I cannot access it. I note that the Mac is assigning my wireless device an IP address in the private range.

Small diagram:

Wireless device ---- Mac ----- Other computers on network

However, it works like this:

Wireless device ---- Mac ----|---- Other computers

I simply cannot see them.

The Mac can see the other computers.

Thanks for the help.

Answer 1

When Internet Sharing is on, your Mac is acting as a NAT gateway, not an Ethernet bridge, so it'll block most service discovery and local name resolution protocols such as Bonjour, which use non-routable multicasts (and some old-school bad ones like NetBIOS that use broadcasts). So if you're trying to browse for services on the far side of your Internet Sharing Mac, or if the app you're running automatically uses Bonjour to find other things to connect to, it'll fail.

From the wireless devices, can you ping devices on the far side of the Internet Sharing Mac using IP address?

Another thing to check: I believe Internet Sharing hard-codes its NAT private address range to 10.0.2.x/24. Make sure the network on the far side of your Internet Sharing machine is not using that same subnet, otherwise your Internet Sharing Mac's route table will likely get confused (to put it mildly).