0

I have a wired network setup like here:

router (192.168.1.1) to internet
192.168.1.2 computer
192.168.1.3 computer
192.168.1.4 Mac pro 10.0.1.2 --- wireless --- 10.0.1.1 AirPort Express --- speaker
[The AirPort Express is a router with built-in audio output]

The AirPort is configured for a stand-alone network—no internet sharing, guest WLAN, etc. Now I would like to send audio from one of the other computers to the speaker.

When I set up a route to the 10.0.1.x/24 network via 192.168.1.4 AND enable forwarding on the Mac, I can ping its 10.0.1.2 address. However, I can only ping the AirPort right from the Mac, but not from the other computers.

Which settings would I need to change to make this work? From experience with other routers, I would expect that it somehow needs to be told that it should send return packets to the 192.168.1.0/24 network via the Wi-Fi connection?

1 Answer 1

0

It would be best if you found a way to connect your AirPort Express directly to your home network, and disable NAT and DHCP service in the AirPort Express. It can just be a simple bridge or a client device since you've already got a router doing NAT and DHCP service for your network.

If you really wanted to make it work with the Mac Pro being the way the AirPort Express connects to the network, you could probably make it work by using Internet Sharing on the Mac Pro to make it act as a Wi-Fi AP (and home gateway router), but then do something to block it from being a DHCP server on its wireless interface (kill bootpd, or use ipfw or pf to block bootpd's packets from getting out), and then create a bridge device and add the Ethernet and the Wi-Fi interface to the bridge device. Then reconfigure the AirPort Express to join the Mac Pro's Wi-Fi network as a client.

You need to be bridging the AirPort Express's traffic onto your home network, otherwise iTunes (or other AirTunes/AirPlay clients) won't see the Bonjour service advertisements, and thus won't know that an AirTunes/AirPlay speaker device is on the network. Also, AirTunes (at least used to) have a restriction where it would only play to devices on the same IP subnet. So putting your AirPort Express on a different subnet than your home network probably won't work.

The "needs to be on same IP subnet" issue is also why I suggest you make sure to block your Mac Pro from acting as a DHCP server (which is something Internet Sharing automatically turns on). Because if your AirPort Express gets a DHCP lease from your Mac Pro, it won't be on the same IP subnet as the rest of your network, so AirTunes will probably balk.

One other possibility to avoid running Internet Sharing is that you could try putting your Mac Pro's Wi-Fi interface into IBSS (a.k.a. "ad hoc", "computer-to-computer", etc.) mode, but I don't think AirPort Expresses support joining IBSS networks. So you need to put your Mac Pro's Wi-Fi interface into real Access Point (AP) mode, which is what Internet Sharing does. I don't know of an easier way of putting the Wi-Fi interface into AP mode other than starting up Internet Sharing. I don't think you can trigger that mode with ifconfig, airport, airportd, networksetup, or anything else that I know of.

3
  • Hi, thanks for detailed response. At some time in the future I will try running an ethernet cable to that nice box sitting on top of the speaker :) - I have to convince somebody to drill a hole. Setting up a bridged connection does make sense (in particular since you mention the "only works on local subnet" problems). But, to be honest, I just dont know how to setup things, and network preferences do not really offer complex settings. Same holds true for the program that configures the airport express. Do you have any pointers where I could learn more about network stuff? Nov 24, 2013 at 10:28
  • @user1938139 Is your main router really wired-only? If so, it might be easiest to replace it with a Wi-Fi router and have the AirPort Express join that router as a wireless client.
    – Spiff
    Nov 24, 2013 at 21:24
  • another "sometime in the future" project - I guess that running a wire to the airport would be better solution at the moment Nov 25, 2013 at 4:34

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .