underparhi
Level 1 (0 points)

Q: Ethernet port not working

I plug my modem into the my iMac ethernet port and does not show any connection. the router is working fine I plug it into my macbook and connects seamlessly. Is there any way I accidentally turned off my ethernet port? Other than just plugging it in it has always showed connected., whenever cable was plugged in. Any suggestions?

 

Mahalo,

Keith

iMac, OS X Mavericks (10.9.5)

Posted on Aug 7, 2015 8:18 PM

Close
underparhi

Q: Ethernet port not working

  • All replies
  • Helpful answers

  • by BobHarris,

    BobHarris BobHarris Aug 8, 2015 8:11 AM in response to underparhi
    Level 6 (19,292 points)
    Mac OS X
    Aug 8, 2015 8:11 AM in response to underparhi

    First, many cable modems lock into the first MAC (Media Access Control) address it sees after the cable modem powers up and does not talk to any other device until the cable is power cycled again.

     

    Or is the a combination cable modem AND router with several LAN Ethernet ports.  That would not be an issue for those ports.

     

    System Preferences -> Network, on the left side, you see the different networking interfaces.  Wi-Fi, Ethernet, FireWire (maybe), Bluetooth, Thunderbolt (maybe).

     

    If you do NOT see "Ethernet", then that would explain it.  In this case, you would go to the [+] icon at the bottom of that list and click it.  Select "Ethernet" from the "Interface" popup list.

     

    If you "Do" have an "Ethernet" interface, and it is not connecting when you have a Ethernet cable connected, you need to check the settings it receives when the cable is plugged in.  Click on the "Ethernet" interface.  Click "Advanced"

    • What does the TCP/IP tab say?
    • What does the DNS tab say?
    • What does the Proxies tab say (hopefully it doesn't say anything - no boxes checked; proxies are typically used in a corporate office)
    • What does the Hardware tab say

     

    You also need to be sure the cable is good.  Did you use the same Ethernet cable for other working systems?