Ethernet problem - Puzzling

Discussion in 'macOS' started by Cerebrus' Maw, May 6, 2010.

  1. Cerebrus' Maw macrumors 6502

    Mar 9, 2008
    Brisbane, Australia
    Well, this is odd.

    My airport is working fine, but everytime I connect my ethernet cable, it kills my internet. I just get a continuos white page, with waiting for Google at the bottom (or whatever website I try) Kills it instantly, within a second I would say.

    Ethernet is getting good IP address from router, and is using the same DNS as Airport.
    I've tried the usuals including:

    Power cycle everything,
    Turn off airport while trying the ethernet,
    new Location,
    Different User account,
    Tried URL address and IP address,
    Different Browsers,
    From Terminal: dscacheutil -flushcache
    Used Different computer, works fine
    reset PRAM

    Whats odd, is that I cant even log into my router. Also, even though I cant reach these websites, I can ping them. Trace route does show an interesting problem where I dont seem to get out of my ISP's servers.
    traceroute: Warning: has multiple addresses; using
    traceroute to (, 64 hops max, 52 byte packets
     1 (  1.026 ms  0.660 ms  0.568 ms
     2  * (  17.727 ms  17.392 ms
     3 (  20.766 ms  21.761 ms *
     4  * (  84.378 ms  31.651 ms
     5 (  30.342 ms *  31.713 ms
     6 (  30.363 ms *  40.002 ms
     7 (  30.349 ms  30.414 ms *
     8 (  31.115 ms *  30.417 ms
     9  * * *
    Also, under network utility->info, I seem to have an unusually high Recv Errors. Recv Packets:396, Recv Errors:349

    I ran tcpdump -n -i en0 port 53 from terminal and got this:
    tcpdump: WARNING: en0: no IPv4 address assigned
    tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
    listening on en0, link-type EN10MB (Ethernet), capture size 65535 bytes
    03:27:50.029469 IP > 1831+ PTR? (42)
    03:27:50.115771 IP > 1831 NXDomain 0/0/0 (42)
    03:27:52.940554 IP > 349+ A? (38)
    03:27:53.041436 IP > 32196+ AAAA? (38)
    03:27:53.303032 IP > 32196 1/0/0 CNAME (67)
    03:27:53.391666 IP > 56895+ A? (46)
    03:27:53.491742 IP > 24092+ AAAA? (46)
    03:27:53.708753 IP > 24092 0/0/0 (46)
    03:27:54.192362 IP > 56241+ PTR? (43)
    03:27:54.492418 IP > 56895+ A? (46)
    03:27:54.535936 IP > 56895 1/0/0 A (62)
    03:27:55.194160 IP > 56241+ PTR? (43)
    03:27:55.212982 IP > 56241 NXDomain 0/0/0 (43)
    03:27:55.216081 IP > 18145+ PTR? (44)
    03:27:56.218021 IP > 18145+ PTR? (44)
    03:27:56.237634 IP > 18145 NXDomain 0/0/0 (44)
    03:28:18.740472 IP > 4653+ A? (36)
    03:28:19.742866 IP > 4653+ A? (36)
    03:28:22.748700 IP > 4653+ A? (36)
    03:28:22.769395 IP > 4653 1/0/0 A (52)
    03:28:54.230828 IP > 42061+ A? (41)
    Any help would be massively appreciated.
  2. wrldwzrd89 macrumors G5


    Jun 6, 2003
    Solon, OH
    Bad cable, perhaps? Try a different cable between your computer and the wall Ethernet port.
  3. Cerebrus' Maw thread starter macrumors 6502

    Mar 9, 2008
    Brisbane, Australia
    My thought also, but I used the exact same cables when I used the other computer, and that worked fine.

    Edit: Also, this broadband comes over the phone line, so my box is a modem/router. Cant direct connect to the wall.
  4. wrldwzrd89 macrumors G5


    Jun 6, 2003
    Solon, OH
    So it's not the cable... the next thing to check is the settings on the router and computer. Some ISPs require MAC address cloning for authentication purposes, for example. It could be that the other computer you tried is set up properly for Internet access, while the first computer is not (at least not for Ethernet).
  5. Cerebrus' Maw thread starter macrumors 6502

    Mar 9, 2008
    Brisbane, Australia
    Right, gonna hard reset my router.

    Regarding the authentication, there was nothing like that when I setup the internet here (i ordered/setup etc)

    In fact, I think initial setup could only be done via cable...
  6. Cerebrus' Maw thread starter macrumors 6502

    Mar 9, 2008
    Brisbane, Australia
    ok, problem definitely seems to be on the Mac side.

    Reset my router, and the macbook still couldnt connect to it. Its odd. It seems to resolve domain names, but then just waits....and waits....
  7. ewilson6 macrumors 6502

    Nov 30, 2006
    Run network diagnostics and then post your picture here.

    Network diagnostics will definitley tell you where the problem is.

    Don't make a lifetime issue out of something simple to fix.

  8. Cerebrus' Maw thread starter macrumors 6502

    Mar 9, 2008
    Brisbane, Australia

    This is the problem. To all intents and purposes, my mac thinks I am connect to the net. I can ping, lookup and stat and traceroute.
    It just seems that my mac wants nothing to do with any data that comes from the router.

    Admittedly the traceroute seems a bit iffy, but this could from the packages never reaching my computer, and therefore never being Acked.

    Attached Files:

  9. RandomKamikaze macrumors 6502a


    Jan 8, 2009
    Does IM work? Mail? iTunes? or is just the browser?

    Do you have a proxy configured in network settings?
  10. Mal macrumors 603


    Jan 6, 2002
    I would guess that DNS is the likely culprit. Check the Airport and Ethernet DNS settings, see if they differ. You may have a bad DNS server entered into your Ethernet settings, or none at all (which would mean your ISP's were malfunctioning).

  11. Detektiv-Pinky macrumors 6502a


    Feb 25, 2006
    Berlin, Germany
    Your tcpdump log says: No IP-address assigned.

    Do a ifconfig in Terminal and post the output. It looks like the interface is down / not getting an address from the router.
  12. Cerebrus' Maw thread starter macrumors 6502

    Mar 9, 2008
    Brisbane, Australia

    Thank you Pinky, definitely pointed me in the right direction.

    Under Advanced for the Ethernet communication, went to the Ethernet Tab, and had to changed the Speed from Autoselect down to 10baseT/UTP.

    For your curiosity, here is the ifconfig dump
    lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
    	inet6 ::1 prefixlen 128 
    	inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1 
    	inet netmask 0xff000000 
    gif0: flags=8010<POINTOPOINT,MULTICAST> mtu 1280
    stf0: flags=0<> mtu 1280
    	ether 00:1f:f3:5a:34:98 
    	inet6 fe80::21f:f3ff:fe5a:3498%en0 prefixlen 64 scopeid 0x4 
    	inet netmask 0xffffff00 broadcast
    	media: autoselect (100baseTX <full-duplex,flow-control>)
    	status: active
    	ether 00:1f:5b:b7:5e:a6 
    	inet6 fe80::21f:5bff:feb7:5ea6%en1 prefixlen 64 scopeid 0x5 
    	inet netmask 0xffffff00 broadcast
    	media: <unknown subtype>
    	status: active
    	lladdr 00:1f:f3:ff:fe:6a:8d:d8 
    	media: autoselect <full-duplex>
    	status: inactive
    	ether 00:50:56:c0:00:08 
    	inet netmask 0xffffff00 broadcast
    	ether 00:50:56:c0:00:01 
    	inet netmask 0xffffff00 broadcast
    Edit : Odd that en1 (airport) has Media:Unknown but worked, while en0 (ethernet) had the 100baseTX. Thats what made me think to change it.
    Thanks again guys!
  13. klinkokkos macrumors newbie

    Jun 2, 2010

    I am not familiar with all the terms you use, but I am pretty sure I experience the same problem as you did originally. Being no technician I have tried the following:

    - Testing through cable and trough wireless router
    - Trying different browsers
    - Rebooting and rebooting
    - Checking that everything was set to "automatic"
    - Doing what you did, reduce the speed - had no effect.

    I get the correct IP-address, according to my ISP. I have a whole load of recv errors. I get for example "waiting for", but nothing ever happens.

    I know that the system is working on other networks, but they have different ISP's.

    When talking to the ISP on the phone, all they say is: "Do you have a firewall installed perhaps?".

    Anyone know what this could be?

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