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Thread: Wired connection occassionally drops; pull wire and re-insert fixes the problem.

  1. #1
    Join Date
    Sep 2006
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    22

    Wired connection occassionally drops; pull wire and re-insert fixes the problem.

    I upgraded to 14.04 to try to fix a networking problem. Every so often, the wired connection just drops. I can fix the problem by pulling the ethernet cable out of the wall, and plugging it back in. Sometimes I have to pull a few times, but after a minute or so I'm back online. I've updated the driver for the ethernet card. I suspect it is the card since everything works fine on the old workstation sitting right next to the new one, and except that the old one is running 12.04, everything is configured the same. Actually, I originally install 12.04 on the new machine, but couldn't get it to work, so after a few months, I upgraded to 14.04. Hope springs eternal, but alas, it did not fix the problem.

    contents of /etc/network/interface

    auto lo
    iface lo inet loopback

    auto eth0
    iface eth0 inet static
    address 129.65.56.22
    netmask 255.255.255.0
    gateway 129.65.56.250
    dns-nameservers 129.65.16.254 129.65.21.254

    Here's a route -n while things are running:

    Kernel IP routing table
    Destination Gateway Genmask Flags Metric Ref Use Iface
    0.0.0.0 129.65.56.250 0.0.0.0 UG 0 0 0 eth0
    129.65.56.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
    169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 eth0

    output of ethtool -i eth0

    driver: e1000e
    version: 3.0.4.1-NAPI
    firmware-version: 0.13-4
    bus-info: 0000:00:19.0
    supports-statistics: yes
    supports-test: yes
    supports-eeprom-access: yes
    supports-register-dump: yes
    supports-priv-flags: no

    output of lshw -C network

    *-network
    description: Ethernet interface
    product: 82579LM Gigabit Network Connection
    vendor: Intel Corporation
    physical id: 19
    bus info: pci@0000:00:19.0
    logical name: eth0
    version: 04
    serial: 90:b1:1c:78:87:26
    size: 1Gbit/s
    capacity: 1Gbit/s
    width: 32 bits
    clock: 33MHz
    capabilities: pm msi bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
    configuration: autonegotiation=on broadcast=yes driver=e1000e driverversion=3.0.4.1-NAPI duplex=full firmware=0.13-4 ip=129.65.56.22 latency=0 link=yes multicast=yes port=twisted pair speed=1Gbit/s
    resources: irq:44 memory:f7f00000-f7f1ffff memory:f7f39000-f7f39fff ioport:f040(size=32)


    The network manager thinks things are unmanaged.

    Any thoughts? This is an extension of the post http://ubuntuforums.org/showthread.php?t=2183423. Since updating didn't fix the problem, I thought we could try again.

    Thanks.

  2. #2
    Join Date
    Aug 2011
    Location
    Berlin, Germany
    Beans
    5,929
    Distro
    Ubuntu Gnome 14.04 Trusty Tahr

    Re: Wired connection occassionally drops; pull wire and re-insert fixes the problem.

    Please show the outputs of:

    Code:
    sudo apt-get install ethtool
    sudo ethtool eth0
    cat /etc/NetworkManager/NetworkManager.conf

  3. #3
    Join Date
    Sep 2006
    Beans
    22

    Re: Wired connection occassionally drops; pull wire and re-insert fixes the problem.

    Hi praseodym,

    Here's the output of all those commands:


    brichert@richert:~$ sudo apt-get install ethtool
    [sudo] password for brichert:
    Reading package lists... Done
    Building dependency tree
    Reading state information... Done
    ethtool is already the newest version.
    0 upgraded, 0 newly installed, 0 to remove and 30 not upgraded.
    brichert@richert:~$ sudo ethtool eth0
    Settings for eth0:
    Supported ports: [ TP ]
    Supported link modes: 10baseT/Half 10baseT/Full
    100baseT/Half 100baseT/Full
    1000baseT/Full
    Supported pause frame use: No
    Supports auto-negotiation: Yes
    Advertised link modes: 10baseT/Half 10baseT/Full
    100baseT/Half 100baseT/Full
    1000baseT/Full
    Advertised pause frame use: No
    Advertised auto-negotiation: Yes
    Speed: 1000Mb/s
    Duplex: Full
    Port: Twisted Pair
    PHYAD: 1
    Transceiver: internal
    Auto-negotiation: on
    MDI-X: off (auto)
    Supports Wake-on: pumbg
    Wake-on: g
    Current message level: 0x00000007 (7)
    drv probe link
    Link detected: yes
    brichert@richert:~$ cat /etc/NetworkManager/NetworkManager.conf
    [main]
    plugins=ifupdown,keyfile,ofono
    dns=dnsmasq

    [ifupdown]
    managed=false
    brichert@richert:~$

  4. #4
    Join Date
    Aug 2011
    Location
    Berlin, Germany
    Beans
    5,929
    Distro
    Ubuntu Gnome 14.04 Trusty Tahr

    Re: Wired connection occassionally drops; pull wire and re-insert fixes the problem.

    Code:
     dns-nameservers 129.65.16.254 129.65.21.254
    These nameservers seem to be wrong, change both to one, the router IP 129.65.56.250

    Additionally, change "false" to "true" in the "*.conf" file and reboot.

  5. #5
    Join Date
    Sep 2006
    Beans
    22

    Re: Wired connection occassionally drops; pull wire and re-insert fixes the problem.

    Changing the dns-nameservers kills the connection, alas. I'm at a university and I think that the name-servers as listed are correct. In any event, I'm still waiting on the managed question, and will report back. Thanks for help!

  6. #6
    Join Date
    Sep 2006
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    22

    Re: Wired connection occassionally drops; pull wire and re-insert fixes the problem.

    Changing managed from false to true also seems not to make a difference. Actually, things have gotten worse. Today, for the first time, the pull the plug trick didn't fix things. I tried several times, including rebooting. Eventually, I changed my connection from static to dhcp (as shown below) and can get online via reboot. I don't know if this is a fluke however.

    auto lo
    iface lo inet loopback

    iface eth0 inet dhcp
    #address 129.65.56.22
    #netmask 255.255.255.0
    #gateway 129.65.56.250

    auto eth0


    One interesting thing. Even when I couldn't get online (via Mozilla, or pinging from the command line) ethtool showed the link as connected, so some part of the computer seems to know that I am plugged in, but then things get hung up in the processing! If anyone has any ideas, your help would be greatly appreciated!

  7. #7
    Join Date
    Aug 2011
    Location
    Berlin, Germany
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    Distro
    Ubuntu Gnome 14.04 Trusty Tahr

    Re: Wired connection occassionally drops; pull wire and re-insert fixes the problem.

    What does
    Code:
    ifconfig -a
    cat /etc/resolv.conf
    show if its working or not working?

  8. #8
    Join Date
    Sep 2006
    Beans
    22

    Re: Wired connection occassionally drops; pull wire and re-insert fixes the problem.

    Here's what it says when things are down. I can't seem to get things to come back up without going back to dhcp (and it hasn't crashed yet when I forget about my static ip, although who knows what will happen overnight).

    brichert@richert:/etc/network$ ifconfig -a
    eth0 Link encap:Ethernet HWaddr 90:b1:1c:78:87:26
    BROADCAST MULTICAST MTU:1500 Metric:1
    RX packets:112309 errors:0 dropped:0 overruns:0 frame:0
    TX packets:20646 errors:0 dropped:0 overruns:0 carrier:0
    collisions:0 txqueuelen:1000
    RX bytes:31905254 (31.9 MB) TX bytes:3168732 (3.1 MB)
    Interrupt:20 Memory:f7f00000-f7f20000

    lo Link encap:Local Loopback
    inet addr:127.0.0.1 Mask:255.0.0.0
    inet6 addr: ::1/128 Scope:Host
    UP LOOPBACK RUNNING MTU:65536 Metric:1
    RX packets:1446 errors:0 dropped:0 overruns:0 frame:0
    TX packets:1446 errors:0 dropped:0 overruns:0 carrier:0
    collisions:0 txqueuelen:0
    RX bytes:517620 (517.6 KB) TX bytes:517620 (517.6 KB)

    brichert@richert:/etc/network$ cat /etc/resolv.conf
    # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
    # DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
    nameserver 129.65.16.254
    nameserver 129.65.21.254
    search cosam.calpoly.edu

    While the connection was up and running (with an dhcp instead of static ip address per the interfaces file above) those commands yield:

    brichert@richert:~$ ifconfig -a
    eth0 Link encap:Ethernet HWaddr 90:b1:1c:78:87:26
    inet addr:129.65.56.82 Bcast:129.65.56.255 Mask:255.255.255.0
    inet6 addr: fe80::92b1:1cff:fe78:8726/64 Scope:Link
    UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
    RX packets:110587 errors:0 dropped:0 overruns:0 frame:0
    TX packets:19971 errors:0 dropped:0 overruns:0 carrier:0
    collisions:0 txqueuelen:1000
    RX bytes:31343491 (31.3 MB) TX bytes:3036852 (3.0 MB)
    Interrupt:20 Memory:f7f00000-f7f20000

    lo Link encap:Local Loopback
    inet addr:127.0.0.1 Mask:255.0.0.0
    inet6 addr: ::1/128 Scope:Host
    UP LOOPBACK RUNNING MTU:65536 Metric:1
    RX packets:1382 errors:0 dropped:0 overruns:0 frame:0
    TX packets:1382 errors:0 dropped:0 overruns:0 carrier:0
    collisions:0 txqueuelen:0
    RX bytes:501207 (501.2 KB) TX bytes:501207 (501.2 KB)

    brichert@richert:~$ cat /etc/resolv.conf
    # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
    # DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
    nameserver 129.65.16.254
    nameserver 129.65.21.254
    nameserver 127.0.1.1
    search cosam.calpoly.edu

  9. #9
    Join Date
    Sep 2006
    Beans
    22

    Re: Wired connection occassionally drops; pull wire and re-insert fixes the problem.

    Another bit of news. The ethernet doesn't go down, or at least, didn't go down overnight which is the longest it has ever lasted, when set to dhcp. I still need to get the static ip address up and running, alas.

  10. #10
    Join Date
    Aug 2011
    Location
    Berlin, Germany
    Beans
    5,929
    Distro
    Ubuntu Gnome 14.04 Trusty Tahr

    Re: Wired connection occassionally drops; pull wire and re-insert fixes the problem.

    You are not getting an IPv4 address. Check "sudo dhclient eth0" when its not working.

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