# Solved: Problem with wifi access with Airport Extreme and self-assigned IP numbers



## shawbridge (Aug 19, 2012)

Yesterday, we got broadband access at a vacation house. I purchased and Apple Airport Extreme since we are all Mac Users (we have all Cisco routers at home and office, so maybe that was a mistake but I thought this would make life simple). I password protected the network.

I connected my MacBook Air, ipad 3 and iphone 4s yesterday. No problems and things are working perfectly.

Today, my wife tried to join the network and it says Self-Assigned IP address 169.x.x.x this device may not connect to the internet. So, I deleted the network, and tried again. I rebooted. I rebooted the Airport Extreme. I released DHCP under Advanced. Nothing worked.

I connected the computer to the router via an ethernet cable. The computer recognizes that it is connected to the internet but will not connect.

Today I tried to connect my kids iphones and computer and ipad to the network. I can't make any of them connect.

Is this a problem with the Airport Extreme? Should I return it? Or is this a problem of another kind?


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## JazzySOUL (Apr 26, 2011)

Sounds like your dhcp server isnt working and yet your devices are set to receive IP addresses automatically, not statically. Any IP address that starts with 169 is given by apipa in the absense of dhcp.


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## shawbridge (Aug 19, 2012)

Thanks. So, how do I get the dhcp server to give out IP addresses? Where is the dhcp server (in the router, the modem, or the ISP)? What software do I use to work with the dhcp server?

If that is the explanation, why were the first three devices able to make a connection to the network?


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## JazzySOUL (Apr 26, 2011)

Do the IP adrs of the other devices also start with 169? I think my original diagnosis was wrong. If your other devices are connecting then it means your dhcp is working. That means that your mac isnt setup properly, it doesnt get it's IP adress from the dhcp server because it doesnt know where the dhcp server is. Get to your mac's nic interface and change the settings there so that they point to the dhcp server (probably your router).


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## shawbridge (Aug 19, 2012)

No, the computer that did connect has IP address 192.168.100.100. I don't know about the iphone and ipad (wouldn't know where to look for IP addresses on those).

I have been searching the web and I think there is a chance that this problem crops up when people are using an Airport Extreme or Airport Express. There are a lot of threads about self-assigned IP addresses on Macs, but is it possible that the problem I'm having arises out of some interaction between Airport Extreme and the devices and that I wouldn't have it with, say, a Cisco router (which is what we have at my office and my home)?

How do I access the mac's nic interface? Is there a comparable place to do this with iphones and ipads?


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## shawbridge (Aug 19, 2012)

Problem solved: I called the ISP who said that the router was not defective. He said the router somehow thought that the modem was a router and thus went into bridge mode to allow the other router (is was really a modem) assign IP addresses. So, we used Airport Utility to change the Airport Extreme to DHCP and NAT. This brought up a Double NAT error, which I set to Ignore and now it works and all devices can be on the network.


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## JazzySOUL (Apr 26, 2011)

Glad you solved it. You should mark this post as 'solved'.


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