Macbook cannot get IP address

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Macbook cannot get IP address

Strange Internet problem happened to my Macbook recently.

Two days ago when I started my Mac, I suddenly found out that I cannot connect to the Internet (using cable). In System Preference, the Ethernet status was "Unknown Status" & "the status of your network connection cannot be determined" with no IP address acquired. Then I tried to manually set the IP address to the one I knew, the status changed to green. However, I still cannot access the internet and the "ping" command always returned "no route to host", as no internet connection at all.

It was not only the problem with Ethernet but the same thing happened with AirPort as well.

Currently I suspect it may be a problem of software or system configuration. Can anyone help me out? Thanks!

Macbook 2,1, Mac OS X (10.6.2)

Posted on Mar 22, 2010 8:02 PM

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Answer 1

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William-Boyd-Jr

Level 6

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Mar 22, 2010 8:41 PM in response to zd8472

zd8472 wrote:
Strange Internet problem happened to my Macbook recently.

Welcome to Apple's discussion groups.

Two days ago when I started my Mac, I suddenly found out that I cannot connect to the Internet (using cable). In System Preference, the Ethernet status was "Unknown Status" & "the status of your network connection cannot be determined" with no IP address acquired.

Please describe your networking equipment. If you have cable broadband service, you presumably have a cable modem or equivalent device. What is its brand and model, what else do you have (such as a router), and how is it all connected?

Then I tried to manually set the IP address to the one I knew, the status changed to green. However, I still cannot access the internet and the "ping" command always returned "no route to host", as no internet connection at all.

The IP address is on one of several values that a DHCP server would supply to your computer. As a result, just forcing in an IP address isn't normally effective.

Currently I suspect it may be a problem of software or system configuration. Can anyone help me out?

Until you can describe your networking environment so that people can provide you with specific advice, I'd try unplugging everything for a few minutes, then plug things back in one at a time.

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Answer 2

zd8472 Author

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Mar 22, 2010 8:55 PM in response to William-Boyd-Jr

Thanks for your quick reply!

Here are several information as you requested:
1. I have tried to plug & unplug, restart, shutdown & start for several times, the problem remains.

2. The only information about the networking environment is: I am using the network provided by the university, everything worked fine previously. The normal way is just to plug in and an IP address will be automatically assigned. I don't know much about the device in use, but I would say it does not matter because every other computers (including this one previously) worked quite well.

Are there any tools I can use or any ways for me to do further self-diagnosis?

Thanks & Best regards,
Dan Zhang

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Answer 3

Mar 23, 2010 7:06 AM in response to zd8472

zd8472 wrote:
I am using the network provided by the university, everything worked fine previously. The normal way is just to plug in and an IP address will be automatically assigned.

You might try resetting your connection settings using the steps listed in this message:

http://discussions.apple.com/thread.jspa?messageID=10695921&start=1

They're not guaranteed to solve the problem, but they'll only take you a minute or so to try.

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Answer 4

zd8472 Author

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Mar 23, 2010 8:17 AM in response to William-Boyd-Jr

Dear William,

I tried all the 4 methods in the post but the problem remained... I am wondering now if it is sort of hardware problem... Thanks anyway!

Best,
Dan

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Answer 5

Mar 23, 2010 8:57 AM in response to zd8472

zd8472 wrote:
I tried all the 4 methods in the post but the problem remained... I am wondering now if it is sort of hardware problem...

Several thoughts on things to try to help isolate the problem:
- Connecting your Mac to a different Ethernet port
- Reversing the Ethernet cable end-to-end
- A different Ethernet cable
- Looking in System Profiler (Apple menu -> About This Mac -> More Info) to see if there's an "Ethernet" entry under the "Network" item.

I realize that some of these things approach the trivial, but sometimes the solution to a problem can be trivial.

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Answer 6

zd8472 Author

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Mar 24, 2010 3:52 AM in response to William-Boyd-Jr

I've tried them all but none worked.... is there any more information I can post here which could be of help? Otherwise I have to re-install the system... 😟

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Answer 7

zd8472 Author

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Mar 24, 2010 9:33 AM in response to zd8472

OK, now the problem was fixed, by restoring one of my previous HD copy. Luckily I had the time machine, but I would never know what was wrong...
Thanks guys for all your help! I cannot wait any longer for the solution because it really made me crazy.

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Answer 8

jbrejcha

Level 1

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Mar 27, 2010 2:00 AM in response to zd8472

Try resetting the firmware by hoding cmd-opt-O-F during restart, then type
0 > reset-nvram
Press Return
0 > reset-all
Press Return

This solved the issue on my iBook.

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Answer 9

Apr 9, 2010 8:37 AM in response to zd8472

Resetting the firmware solved the problem on my iBook as well.
Thanks for the tip!

Try resetting the firmware by hoding cmd-opt-O-F during restart, then type
0 > reset-nvram
Press Return
0 > reset-all
Press Return

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Answer 10

Apr 15, 2010 8:01 PM in response to jbrejcha

jbrejcha wrote:
Try resetting the firmware by hoding cmd-opt-O-F during restart, then type
0 > reset-nvram
Press Return
0 > reset-all
Press Return

Thanks a million for that, had to do that to fix my PowerBook G4. Neither Ethernet nor Airport would get a valid IP, even when properly connected.

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