Ethernet port is not working - any tips?

Discussion in 'Mac Basics and Help' started by mmmorgan, Jan 17, 2009.

  1. mmmorgan macrumors newbie

    Jan 17, 2009
    I bought an iMac a little over a year ago. It's running Version 10.5.5 and for a Processor: 2 GHz Intel Core 2 Duo.

    I noticed my internet had been running ultra slow the past few days and didn't know why. I haven't paid attention to it much because I haven't been around. Today I started messing around with my cables, restarted the comp, shut it down.. a lot of stuff just trying to figure out why it was running so slow. When I unplugged the Wireless Router to try and run an Ethernet cable directly from my cable modem to the computer I couldn't access the internet at all. When I use the same Ethernet cable and connect only the cable modem and wireless router I pick up a signal on AirPort and I can access the internet.

    So I know my problem is not with a bad Ethernet cable.. the only explanation is that there is a problem with the Ethernet port in the back of the iMac.

    Does anyone have any experience or tips with this problem?
  2. MarkMS macrumors 6502a

    Aug 30, 2006
    I've never had experience with this type of a problem, but you can always run the Apple Hardware Test (AHT). That should let you know if there is a problem with the ethernet itself. If there is a problem with the hardware, then only Apple can help you. If the test says that the ethernet is running fine, then it may be just a setting or something in OS X. Let us know what happens after the test so we can help you more.
  3. nakile macrumors regular

    Jun 30, 2007
    I would open System Preferences and go into Network and see what it says under the Ethernet section. That might give you a clue as to what is going on.
  4. ewilson6 macrumors 6502

    Nov 30, 2006
    run network diagnostics, It will tell you exactly were the problem is.
  5. mmmorgan thread starter macrumors newbie

    Jan 17, 2009
    Hey guys, thanks for the tips. I ran the disc but I had no luck with that. I did the standard test and also the advanced test, both said there is no problem.

    Under the Ethernet section in Networks it says, "Built-in Ethernet has a self-assigned IP address and may not be able to connect." I have the option to configure.. Using DHCP, Using DHCP with manual address, Using BootP, or manually.
  6. bizzle macrumors 6502a

    Jun 29, 2008
    Run the combo update for 10.5.6, do not use software update.

    If that does not resolve the issue and you are confident that it's not a hardware issue, but software (which I've seen A LOT of in the field), performing an archive and install is usually the fastest way to fix the issue without digging too deep.
  7. kwood macrumors 6502a


    Jun 26, 2006
    In the Great White North.
    If you are getting a self assigned IP Address (169.254.x.x) there is a communication problem between your computer and whatever is plugged into it. You need to power cycle your modem (I recommend 5 minutes) and you should get a valid IP Address. Then plug the modem back into the router and you should be set. If the Internet stops working when the modem is plugged back into the router then simply power-cycle again.

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