MacBook AirPort no longer works – “self assigned IP”

By | July 8, 2009


This has been an absolutely frustrating few hours (I’m trying hard not to think about how long I’ve fiddled with this issue, ugh).

Last night my (mostly) brand new MacBook stopped working. My wife’s connection was still working and so was my laptop running Ubuntu. Weird.

First Stab at Troubleshooting

Ping Nothing.

Ping Nothing.

Turn off/on AirPort? No good.

Turn off/on the MacBook? No good.

Sanity check: ping Great, I could get home, but I couldn’t get away.

Self-Assigned IP

I finally managed a clue to the problem beyond the vauge “it doesn’t work anymore”. While digging into the networks settings and making sure everything at least looked okay, everything did not look okay. In fact, one thing looked very wrong: you’re using a “self assigned IP address, may not be able to connect to internet“.

So I was off to Google for hours of fruitless searching.

Following the Cookie Trail

After manually specifying my DHCP setting, three new clues surfaced in succession.

The first clue: I could still connect to my Ubuntu laptop running a Hudson and Sonar install for my upcoming presentation.

The second clue: I could not connect to my router’s browser interface (nor could I ping it).

The third clue: KisMAC was running like a champ.

With DHCP settings manually configured and successfully connecting to at least something on the router, what could possibly be wrong?

By this point my wife was no longer asking “what’s wrong?” every time I let out a deep sigh.

Villechaize: Ze clue! Ze clue!

After removing the manual DHCP settings, I tried again. Same problem about a “self assigned IP”. Apparently millionth time was not a charm (supposedly this is the definition of insanity).

Desperately, I decided to take a peak at my router’s logs. I don’t know what prompted this, but it turns out it was my final piece to the puzzle:

Jul 7 20:15:28 dnsmasq[733]: DHCPINFORM(br0) nnn.nnn.nnn.nnn xx:xx:xx:xx:xx:xx
Jul 7 20:15:28 dnsmasq[733]: DHCPACK(br0) nnn.nnn.nnn.nnn xx:xx:xx:xx:xx:xx

I must be blocking something, somehow.


Great Success!

I took a guess and disabled the software firewall. Changing the firewall from “set access for specific services and applications” to “allow all incoming connections” did the trick. Great success!

I remember turning on the “set access for specific services and applications” a long long long time ago. So why did it take so long to surface? I’m really not sure. Right now I’m just hoping this really was my problem.

One thought on “MacBook AirPort no longer works – “self assigned IP”

  1. brian

    This sounds like the same sort of thing that baffled me with my daughters pc. We had checked the software firewall setting to block all incoming and outgoing stuff without realizing it. So I’m not the only one! That always makes me feel good. My foot is healing nicely.


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