DNS name resolution failure while using bridged wi-fi connection

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Trying to connect my new Raspberry Pi to the internet for the first time. The Raspi is connected via a cross-over cable to the LAN port of my laptop. The laptop port is then bridged with the laptop's wi-fi using the Win7 built-in network bridge and so should be sharing the internet access in theory.

When using the Raspi browser, it works for any internal network webservers but won't receive anything from the WAN using either URL or ip address. I get a name resolution failure and a fail to load page when attempting anything destined for the WAN.

I'm thinking it must be router related as it only fails if going through the gateway router.

Any ideas what the issue might be and how to resolve it?

Chef Flambe

Posted 2013-01-03T05:19:25.657

Reputation: 157

Answers

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You can't bridge to a WiFi client connection. If you could, we wouldn't need WDS.

Unfortunately, WiFi is just enough like Ethernet to make people think that wireless connections work like wired connections. They don't. WiFi is its own protocol with its own rules. In particular, access points will not bridge to their clients.

An access point will not wirelessly broadcast traffic that isn't to one of its clients unless specifically configured to do so. Devices bridged to your laptop are not clients of the access point, so the access point will not transmit their traffic over the wireless link. If this "just worked" you wouldn't have to specifically configure WDS.

You have two possible solutions:

  1. Configure proxying or Internet connection sharing in the laptop. That will make traffic to the Pi appear to be for the laptop and the access point will transmit it since the laptop is its client.

  2. Obtain an access point and configure it in client mode, connect the Pi to that. This will make the Pi a client of the access point.

David Schwartz

Posted 2013-01-03T05:19:25.657

Reputation: 58 310

Guess I didn't state it clearly enough. The Raspi is connected to the laptop's wired LAN port via a crossover cable. The wi-fi adapter and the wired LAN card are being bridged by the Win7 OS thus allowing a shared internet connection. The problem is that WAN traffic doesn't make it's way back to the Raspi but all LAN traffic does. [I'll edit my question for clarity.] – Chef Flambe – 2013-01-03T06:08:50.253

I understand that. That won't work. You can't bridge to a WiFi client connection. That does not allow a shared Internet connection. The access point won't send the Pi's traffic to the laptop because the Pi is not its client. – David Schwartz – 2013-01-03T09:51:05.157

Sorry David, the facts prove otherwise. In fact I have it working right now. Think the issue was either the router or my laptop as I rebooted both during the night and now the problem is resolved. – Chef Flambe – 2013-01-03T18:48:58.033

@ChefFlambe: I'm not sure how your configuration is working, but most likely it's because the laptop isn't actually bridging. (You can test this. Ping the Pi from another machine on your LAN and see if you get the laptop's MAC address in your ARP table or the Pi's. If you don't get the Pi's, the laptop isn't bridging.) – David Schwartz – 2013-01-03T20:36:44.217

Microsoft calls it a bridge. It's probably more like a PAT/NAT. Just read a MS article saying it automates stuff and creates subnets. Doesn't really matter. It works. – Chef Flambe – 2013-01-04T00:51:15.583