MacBook Local Link Address — can it be fixed?

I have a bad, bad networking problem with my wife’s MacBook. She can’t connect to the internet anywhere, but I am working with my Netgear WNDR3300 for this problem.

Our wireless router is dd-wrt based (open source router firmware), and works fine for about 20 other nodes (other laptops, guests, mobile devices, etc). A couple of details were helpful to start with. Her MacBook has three interfaces: en0, en1, and fw0.

* en0 Ethernet Network Interface Controller (NIC)
* en1 WiFi Network Interface Controller (NIC)
* fw0 Firewire Networking

The second interface (en1) got an ip of 196.254.153.219 which is a link local address (anything in 169.254.0.0/16) is supposed to mean I didn’t get an ip from the DHCP server. However, I could see 192.168.1.1, which is the local ip for the router. This confused me, because it told me that the radio was working and I was getting some type of ip, ah I just don’t understand how I could get a partial connection to the router.

So I went into the Airport Utility, and got the message that AirPort Utility was unable to find any wireless devices. What! With a connection to the router? I was still confused. How was this possible. I was thinking about trying to reseat the wireless card, looking at buying a new wireless card, but that seemed like a lot of work that might not even solve the problem.

Edit, the Airport Utility is not for wireless interfaces, it is for Airport Express/AppleTV like items

I tried to ping google’s DNS server 8.8.8.8, with no host.

The first thing I did was try to manually set the IP to avoid a DHCP error, but the Airport utility said I had no devices.

I was able to ping the wan port (172.27.35.xxx), but I couldn’t ping the public ip (74.96.53.xxx) from verizon dsl. So I thought the issue was my modem, but the laptop was having connection problems, so I figured I had to reseat the wireless card. OSX said I had an AirPort extreme, Broadcom BCM43xx 1.0 (5.10.91.21). Hmm . . . looks connected, but maybe it’s loose? I’m out of options.

From the software, I found my wife has a MacBook5,2, which from Wikipedia is the MB881*/A with the Integrated 802.11a/b/g and draft-n (n enabled). I followed the guide here to confirm the card is in correctly: http://www.ifixit.com/Guide/Repair/Installing-MacBook-Core-2-Duo-AirPort-Card/519/ and everything checked out just fine. That took a lot of time, but confirmed that the card is not loose.

Then I went into network settings and set a manual ip. My subnet mask is 255.255.255.0 with a dhcp server serving from 192.168.1.100 with 50 maximum dhcp users. I am also using opendns for content filtering and speed advantages. So I went into network settings and assigned an IPv4 address of 192.168.1.80 with the correct subnet and router address. I next went to terminal and used ifconfig to see my ip on en1 was 192.168.1.80 and broadcast of 192.168.1.255, media was listed as autoselect status: active.

And . . . I got ping returns from 8.8.8.8 and 4.2.2.2 — name servers I used for testing. However, my default test mit.edu returned nothing (the same with www.google.com). I was able to load http://74.125.225.18 (the site for google).

O.K. so then i knew it was a DNS problem. I hit the terminal with dscacheutil -flushcache to flush the cache, and then restarted. I was worried in that I couldn’t find my NAS on my network, but I hoped a restart would cure all ills. It didn’t: still no www.mit.edu or www.yahoo.com. Hmm . . . Branes from #mac on irc recommended that I manually add the DN servers from OpenDNS. I added the standard 208.67.222.222 and 208.67.220.220 in the advanced mac en1 settings . . . and . . . working great.

Still don’t know why I was getting a local link address. Oh well, it is working just fine now. Any thoughts appreciated.

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