This has been my problem for about 6 months. On my 2011 MBP, if I connect a working ethernet cable to my ethernet port, it will either do nothing or my internet connection will die totally, even when I'm on a strong wifi network.

More intriguing (frustrating), when I jump on a network connected to a simple switch, I have no internet connection. I.E ping www.google.com gets request timeouts or unreachable hosts. But I can run ifconfig en0 ..., then ssh into another computer on the network, and from that ssh terminal I can connect to the internet no problem. My 'network', by the way, is just my laptop and a desktop connected to a network switch. This happens on multiple switches from different companies.

I've reset everything in Network Preferences, but no help. Has anyone seen this behavior? If so, what can I do to fix it?

  • What, exactly, is the other end oth the eth cable connected to?
    – user44427
    Jun 4, 2013 at 14:42
  • do you use any proxy in your network management ? Jun 4, 2013 at 16:28
  • Both computers are connected via ethernet to a network router. I am not using a proxy protocol, but under "Network Preferences -> Ethernet -> Proxies -> Bypass proxy settings for for these hosts and these domains", I have "*.local, 169.254/16" I don't recall adding these, but might have some time in the past
    – zachd1_618
    Jun 4, 2013 at 19:51
  • Hey did you ever get this resolved?
    – Deesbek
    Nov 6, 2013 at 14:09
  • Yes I did. Root cause is unknown. But I created a new ethernet interface in Network Preferences and set that as the default. Seemed to do the trick
    – zachd1_618
    Nov 7, 2013 at 16:38

1 Answer 1


I don't have enough reputation yet to add comments above, so I'll put my questions here:

  • How does your MBP get the IP address for its ethernet interface? DHCP? Manually?
  • What is your default router set to (netstat -rn)?
  • Can you resolve, say, google.com (nslookup www.google.com)?
  • Can you ping any/all the servers mentioned in /etc/resolv.conf?

That should help to debug.


  • 1. IPV4: DHCP. IPV6: Automatically. 2. Looks like default is set to link#10 Gateway, and netif is bridge0. 3. nslookup failed. 4. All pings had "no rout to host"
    – zachd1_618
    Jun 5, 2013 at 22:16
  • @zachd1_618 If I type netstat -rn | fgrep default I get default UGSc 30 0 en0, the default router is the second field, in my case. Can you ping your default router? Jun 6, 2013 at 11:53

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