I have an Intel iMac, 2.16 GHz Core 2 Duo running Mac OS 10.4.10 and an Intel MacBook, 2GHz Core 2 Duo running Mac OS 10.4.11 connected to a wireless D-Link DI-624 router using Airport. There is also a Windows desktop connected using Ethernet cable. They all work just fine. I decided to hook up the iMac via Ethernet cable. I turned off Airport. I tried to configure the Ethernet cable hookup and every time I’d get that DHCP has assigned a very strange IP. It should be 192.168.0.XXX, but the indicated IP is something like 235.67.0.45 and the Subnet Mask is 255.255.0.0 instead of 255.255.255.0. I thought maybe it was the iMac so I hooked up the MacBook and got the same results. Neither computer would connect to the internet. I even tried other ports on the router.

A Class "D" address? Cool! Maybe the Windows machine is serving DHCP ...?

I'd try giving each computer a manual address. Just note the TCP/IP info that appears when it's connected wirelessly and use that to configure the TCP/IP settings under Ethernet.

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MacMagus
A Class "D" address? Cool! Maybe the Windows machine is serving DHCP ...?

I'd try giving each computer a manual address. Just note the TCP/IP info that appears when it's connected wirelessly and use that to configure the TCP/IP settings under Ethernet.

I've inserted the info manually and when I go to network status, the ethernet button shows green and it says I'm connected to the internet, but when I try to connect with the browser - Firefox - it says not connected to the internet. This is driving me crazy. It should be so easy.

I wonder where the IP is coming from. It's almost as though it is getting it directly from the ISP just like the cable modem.

If you can use a browser to get into the router, then the router is the problem.

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Mr. Curmudgeon, on Mountain Lion.

I went into the browser and set the IP to a static IP. The strange IP remains. Under Network Status for Built-In Ethernet it says "Built-in Ethernet is currently active. Built-in Ethernet has a self-assigned IP address and may not be able to connect to the internet."
The ethernet NIC assigned its own IP and disregarded the router?

re-start the router

re-start the Macintosh

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space-time
re-start the router

re-start the Macintosh

I've done that many times. The results are always the same - strange IP and Subnet Mask.

Disconnect the PC from the router. Then restart the router and connect the Mac(s) and leave the PC off. Does it work?

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bad ethernet cable???

Wait... you set a manual address in the TCP/IP section of the Ethernet config in your Network pref's and then when you close and re-open your Network pref's, it reverts back to that 235... address?

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MacMagus
Wait... you set a manual address in the TCP/IP section of the Ethernet config in your Network pref's and then when you close and re-open your Network pref's, it reverts back to that 235... address?

Yes. I just assigned a static IP to the ethernet port through the router's utility and the IP remains the strange one. In Network Status, Built-in Ethernet says: The cable for Built-in Ethernet is connected, but your computer does not have an IP address and cannot connect to the internet.

I just tried connecting a Windows laptop via ethernet. When I connect the ethernet cable a note comes up that says getting IP address. Then it gets the IP address 169.254.18.16 with a Subnet Mask of 255.255.0.0. It lists the Default Gateway as 169.254.18.16. I think perhaps the router might be bad, but then I have a desktop connected to it via ethernet cable and it works just fine - 1 out of 4 lan ports bad? Just used the same port as the desktop and still get the IP address 169.254.18.16 with a Subnet Mask of 255.255.0.0.

All these compters that I'm trying to hook up with ethernet have wireless capability.

> Yes. I just assigned a static IP to the ethernet port through the router's utility and the IP
> remains the strange one.

??

Did you actually enter an IP address, router address and DNS server addresses in the TCP/IP settings in the Network pref's on the computer?



> Then it gets the IP address 169.254.18.16...

That kind of address shows up when a device can't contact a router to receive an address via DHCP.



> 1 out of 4 lan ports bad?

That does happen, but it's pretty rare.

It's more likely that there's something wrong with your configuration.



With the facts at hand, I can't make a good diagnosis. Have you got any friends with networking experience? This might be a good time to offer them a nice dinner or drinks in exchange for a little in-house technical support...

> The cables say "Patch" on them. Could that be the problem?

It seldom hurts to try a different cable.

try a cable that you know it works with the Windows computer.

Also, most new Apple computers have a network port that will switch wires as needed, it does matter if you use a patch cable or a regular cable.

I bought a new cable and tried it. I manually set the IP and Subnet Mask on the computer instead of the usual "Get an IP Automatically". The indications are that the computer is connected okay, but no internet. I finally used the cable to the desk-top. Same results. I was worried that the desk-top would start having the same symptoms once I plugged it back in, but it is okay. I hate to admit it, but this has kicked my butt. Thank goodness for wireless.

recap please

You have a windows computer that connects OK, but the imac or the MacBook cannot connect. None of them. That is very very weird. Seems like your router hates Apples!
(but it doesn't mind when they're hooked up by radio waves)

I also tried a Windows laptop and a laptop running Ubuntu with the same results. The router seems to hate all wireless capable computers. The wireless capability works for all. Seems in the past all I've had to do is plug an ethernet cable into a computer and it just works. This is Guam and things seem to work differently.