My Network! Why hath thou forsaken me?

This is a discussion on My Network! Why hath thou forsaken me? within the Tech Board forums, part of the Community Boards category; Hi, I just downgraded my motherboard to an Asus P5G41C-M and installed Ubuntu 8.10 i386, and at first my network ...

  1. #1
    and the hat of sweating
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    My Network! Why hath thou forsaken me?

    Hi,
    I just downgraded my motherboard to an Asus P5G41C-M and installed Ubuntu 8.10 i386, and at first my network was working fine; then I tried installing Ubuntu 10.04 LTS and my whole system was messed up. So I reinstalled Ubuntu 8.10 and I haven't been able to get a network connection anymore.
    What's going on, and how can I fix it?
    I'm not a Linux expert...
    "I am probably the laziest programmer on the planet, a fact with which anyone who has ever seen my code will agree." - esbo, 11/15/2008

    "the internet is a scary place to be thats why i dont use it much." - billet, 03/17/2010

  2. #2
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    What does ifconfig say?

  3. #3
    and the hat of sweating
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    I'm assuming you just care about eth0 and not lo...
    Code:
    eth0  Link encap:Ethernet  HWaddr e0:cb:4e:ca:da:f0
          UP BROADCAST RUNNING MULTICAST  MTU:1500 Metric 1
          RX packets:0 errors:0 dropped:177140640 overruns:0 frame:0
          TX packets:4 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes 0 (0.0 B)  TX bytes 1368 (1.3KB)
          Interrupt:221  Base address:0x2000
    "I am probably the laziest programmer on the planet, a fact with which anyone who has ever seen my code will agree." - esbo, 11/15/2008

    "the internet is a scary place to be thats why i dont use it much." - billet, 03/17/2010

  4. #4
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    Hm, so it doesn't have an IP.

    Can you try "sudo dhclient" and see what happens? That will try to grab an IP from DHCP.

  5. #5
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    BTW,

    RX dropped:177140640 definitely looks suspicious.

    I'm not quite sure what that means, though.

    My computer has been running for a few days and dropped:0
    Code:
    eth0      Link encap:Ethernet  HWaddr 00:1f:d0:50:f1:11  
              inet addr:192.168.1.111  Bcast:192.168.1.255  Mask:255.255.255.0
              inet6 addr: fe80::21f:d0ff:fe50:f111/64 Scope:Link
              UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
              RX packets:853857 errors:0 dropped:0 overruns:0 frame:0
              TX packets:594850 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:1000 
              RX bytes:1125507474 (1.1 GB)  TX bytes:78095186 (78.0 MB)
              Interrupt:29 Base address:0xc000

  6. #6
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    Can you look through the output of "dmesg" and see if you notice anything that might have to do with the network?

  7. #7
    and the hat of sweating
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    sudo dhclient says:

    Code:
    Listening on LPF/pan0/de:0a:77:ef:47:6a
    Sending on   LPF/pan0/de:0a:77:ef:47:6a
    Listening on LPF/pan0/e0:cb:4e:ca:da:f0
    Sending on   LPF/pan0/e0:cb:4e:ca:da:f0
    Sending on   Socket/fallback
    DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3
    DHCPDISCOVER on pan0 to 255.255.255.255 port 67 interval 6
    DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 8
    DHCPDISCOVER on pan0 to 255.255.255.255 port 67 interval 8
    DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 11
    DHCPDISCOVER on pan0 to 255.255.255.255 port 67 interval 9
    DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 14
    DHCPDISCOVER on pan0 to 255.255.255.255 port 67 interval 11
    DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 17
    DHCPDISCOVER on pan0 to 255.255.255.255 port 67 interval 17
    DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 8
    DHCPDISCOVER on pan0 to 255.255.255.255 port 67 interval 10
    No DHCPOFFERS received.
    No working leases in persistent database - sleeping.
    I'm not sure what all this means in dmesg but here's anything I could see using network terminology (I've also attached the entire dmesg output in case I missed something):

    Code:
    [    0.620224] net_namespace: 840 bytes
    [    0.620262] NET: Registered protocol family 16
    [    0.676041] NET: Registered protocol family 8
    [    0.676044] NET: Registered protocol family 20
    [    0.676065] NetLabel: Initializing
    [    0.676065] NetLabel:  domain hash size = 128
    [    0.676065] NetLabel:  protocols = UNLABELED CIPSOv4
    [    0.676065] NetLabel:  unlabeled traffic allowed by default
    [    0.719543] NET: Registered protocol family 2
    [    0.732069] IP route cache hash table entries: 32768 (order: 5, 131072 bytes)
    [    0.732266] TCP established hash table entries: 131072 (order: 8, 1048576 bytes)
    [    0.732486] TCP bind hash table entries: 65536 (order: 7, 524288 bytes)
    [    0.732598] TCP: Hash tables configured (established 131072 bind 65536)
    [    0.732601] TCP reno registered
    [    0.736089] NET: Registered protocol family 1
    [    1.304325] audit: initializing netlink socket (disabled)
    [    2.004525] r8169 Gigabit Ethernet driver 2.3LK-NAPI loaded
    [    2.004547] r8169 0000:01:00.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17
    [    2.004566] r8169 0000:01:00.0: setting latency timer to 64
    [    2.004580] r8169 0000:01:00.0: unknown MAC (2b3000c0)
    [    2.004890] eth0: RTL8169 at 0xf8842000, e0:cb:4e:ca:da:f0, XID 283000c0 IRQ 221
    [   10.868256] ip_tables: (C) 2000-2006 Netfilter Core Team
    [   12.820402] Bluetooth: Core ver 2.13
    [   12.820480] NET: Registered protocol family 31
    [   12.820487] Bluetooth: HCI device and connection manager initialized
    [   12.820497] Bluetooth: HCI socket layer initialized
    [   12.833443] Bluetooth: L2CAP ver 2.11
    [   12.833449] Bluetooth: L2CAP socket layer initialized
    [   12.843028] Bluetooth: RFCOMM socket layer initialized
    [   12.843043] Bluetooth: RFCOMM TTY layer initialized
    [   12.843046] Bluetooth: RFCOMM ver 1.10
    [   12.847345] Bluetooth: SCO (Voice Link) ver 0.6
    [   12.847353] Bluetooth: SCO socket layer initialized
    [   12.857323] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
    [   12.857330] Bluetooth: BNEP filters: protocol multicast
    [   12.889602] Bridge firewalling registered
    [   12.889743] pan0: Dropping NETIF_F_UFO since no NETIF_F_HW_CSUM feature.
    [   16.924410] r8169: eth0: link up
    [   17.013155] NET: Registered protocol family 17
    [  105.537450] NET: Registered protocol family 10
    [  105.538643] lo: Disabled Privacy Extensions
    [  105.540609] type=1503 audit(1275843999.473:6): operation="socket_create" family="ax25" sock_type="dgram" protocol=0 pid=6006 profile="/usr/sbin/cupsd"
    [  105.542200] type=1503 audit(1275843999.478:7): operation="socket_create" family="netrom" sock_type="seqpacket" protocol=0 pid=6006 profile="/usr/sbin/cupsd"
    [  105.543817] type=1503 audit(1275843999.478:8): operation="socket_create" family="rose" sock_type="dgram" protocol=0 pid=6006 profile="/usr/sbin/cupsd"
    [  105.545382] type=1503 audit(1275843999.478:9): operation="socket_create" family="ipx" sock_type="dgram" protocol=0 pid=6006 profile="/usr/sbin/cupsd"
    [  105.546979] type=1503 audit(1275843999.482:10): operation="socket_create" family="appletalk" sock_type="dgram" protocol=0 pid=6006 profile="/usr/sbin/cupsd"
    [  105.548617] type=1503 audit(1275843999.482:11): operation="socket_create" family="econet" sock_type="dgram" protocol=0 pid=6006 profile="/usr/sbin/cupsd"
    [  105.550234] type=1503 audit(1275843999.486:12): operation="socket_create" family="ash" sock_type="dgram" protocol=0 pid=6006 profile="/usr/sbin/cupsd"
    [  105.551808] type=1503 audit(1275843999.486:13): operation="socket_create" family="x25" sock_type="seqpacket" protocol=0 pid=6006 profile="/usr/sbin/cupsd"
    [  105.553051] type=1503 audit(1275843999.486:14): operation="inode_permission" requested_mask="::r" denied_mask="::r" fsuid=7 name="/proc/6006/net/dev" pid=6006 profile="/usr/sbin/cupsd"
    [  115.776008] eth0: no IPv6 routers present
    [  118.444011] pan0: no IPv6 routers present
    Attached Files Attached Files
    "I am probably the laziest programmer on the planet, a fact with which anyone who has ever seen my code will agree." - esbo, 11/15/2008

    "the internet is a scary place to be thats why i dont use it much." - billet, 03/17/2010

  8. #8
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    I don't see anything wrong from dmesg, either.

    dhclient never gets a reply, but we don't know why.

    You can try giving it a static IP in /etc/network/interfaces, but I doubt that will help.

    Do you have another computer that you can try (using the same cable and same port)?

    If another computer works, I would say it's probably hardware failure.

    Driver trouble would be unlikely since Realtek cards are very Linux friendly, and millions of people use that driver. And you've reinstalled already.

    If you have a PCI network card lying around, I would try that, too. Or pick one up for $10 or something. You can get a gigabit one for $15 now I think.

  9. #9
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    Try looking through the router if it has any logs on what went wrong. I'm not sure if there usually is any, though. Make sure the cable works (with another computer, maybe?). Try a different router port, if possible. The hardware of the computer remained the same? I mean, if not, your router may be configured to allow only MAC addresses but I can't imagine an ubuntu reinstall changes the MAC address ;-) (even though you CAN change it manually).

    If the router and cable both are fine then it might be a fairly difficult to trace bug..

  10. #10
    and the hat of sweating
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    OK, this is really strange...
    After I installed an old 3com NIC, BOTH network jacks worked. Maybe my first NIC was lonely?
    Anyways, thanks for the help. I guess I'll just file this under the strange and unexplained category of computer problems.
    "I am probably the laziest programmer on the planet, a fact with which anyone who has ever seen my code will agree." - esbo, 11/15/2008

    "the internet is a scary place to be thats why i dont use it much." - billet, 03/17/2010

  11. #11
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    I would say it's just dying hardware.

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