Wired internet connection drops randomly

[carwe]

Hi,

I'm running Ubuntu 12.04 on an HP 6730b laptop. Sometimes my wired internet access just drops. I can get it back by simply rebooting, but I haven't found any other way (disable/enable network or restarting network manager doesn't help).

This has happened two times now within one week. Not too much, but since I have to reboot it's quiet annoying.

Some more info:

- I can ping 127.0.0.1 but not external websites

- Both LEDs at the ethernet connector are active (green is lit, orange is blinking irregularly)

- I tried disabling ipv6 (by doing this: http://www.noobslab.com/2012/05/disa...ternet-is.html), didn't help

- When the wired connection has dropped, if I enable wireless, the wireless connection works fine

I have attached the output of a number of terminal commands under this message that might give you guys some info. These commands were run when the connection had been dropped (and before I rebooted).

Thanks, Carl

$ uname -a
Linux my-laptop 3.2.0-29-generic-pae #46-Ubuntu SMP Fri Jul 27 17:25:43 UTC 2012 i686 i686 i386 GNU/Linux
$ 
$ 
$ lspci -nnk | grep -iA2 net
02:00.0 Network controller [0280]: Intel Corporation PRO/Wireless 5100 AGN [Shiloh] Network Connection [8086:4237]
	Subsystem: Intel Corporation WiFi Link 5100 AGN [8086:1211]
	Kernel driver in use: iwlwifi
--
85:00.0 Ethernet controller [0200]: Broadcom Corporation NetLink BCM5787M Gigabit Ethernet PCI Express [14e4:1693] (rev 02)
	Subsystem: Hewlett-Packard Company Device [103c:30dd]
	Kernel driver in use: tg3
$ 
$ 
$ lsmod
Module                  Size  Used by
btusb                  17912  2 
rfcomm                 38139  16 
bnep                   17830  2 
bluetooth             158438  23 btusb,rfcomm,bnep
dm_crypt               22528  0 
binfmt_misc            17292  1 
snd_hda_codec_analog    75395  1 
snd_hda_intel          32765  2 
snd_hda_codec         109562  2 snd_hda_codec_analog,snd_hda_intel
snd_hwdep              13276  1 snd_hda_codec
snd_pcm                80845  2 snd_hda_intel,snd_hda_codec
snd_seq_midi           13132  0 
snd_rawmidi            25424  1 snd_seq_midi
snd_seq_midi_event     14475  1 snd_seq_midi
snd_seq                51567  2 snd_seq_midi,snd_seq_midi_event
snd_timer              28931  2 snd_pcm,snd_seq
arc4                   12473  2 
snd_seq_device         14172  3 snd_seq_midi,snd_rawmidi,snd_seq
uvcvideo               67203  0 
videodev               86588  1 uvcvideo
joydev                 17393  0 
tpm_infineon           17296  0 
snd                    62064  13 snd_hda_codec_analog,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_pcm,snd_rawmidi,snd_seq,snd_timer,snd_seq_device
iwlwifi               291907  0 
soundcore              14635  1 snd
snd_page_alloc         14108  2 snd_hda_intel,snd_pcm
hp_accel               25728  0 
psmouse                72919  0 
lis3lv02d              19268  1 hp_accel
hp_wmi                 13652  0 
serio_raw              13027  0 
sparse_keymap          13658  1 hp_wmi
input_polldev          13648  1 lis3lv02d
mac80211              436455  1 iwlwifi
cfg80211              178679  2 iwlwifi,mac80211
mac_hid                13077  0 
tpm_tis                18308  0 
ppdev                  12849  0 
parport_pc             32114  1 
lp                     17455  0 
parport                40930  3 ppdev,parport_pc,lp
firewire_ohci          40172  0 
firewire_core          56906  1 firewire_ohci
crc_itu_t              12627  1 firewire_core
tg3                   141369  0 
wmi                    18744  1 hp_wmi
i915                  414739  3 
drm_kms_helper         45466  1 i915
drm                   197692  4 i915,drm_kms_helper
i2c_algo_bit           13199  1 i915
video                  19068  1 i915
$ 
$ 
$ 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 127.0.0.1
$ 
$ 
$ ifconfig -a
eth0      Link encap:Ethernet  HWaddr 00:25:b3:5b:f9:d3  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
          Interrupt:17 

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:16436  Metric:1
          RX packets:352221 errors:0 dropped:0 overruns:0 frame:0
          TX packets:352221 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:72775884 (72.7 MB)  TX bytes:72775884 (72.7 MB)

wlan0     Link encap:Ethernet  HWaddr 00:22:fa:ec:20:28  
          BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:31220 errors:0 dropped:0 overruns:0 frame:0
          TX packets:25120 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:34701734 (34.7 MB)  TX bytes:3582954 (3.5 MB)

$ 
$ 
$ rfkill list
0: hp-wifi: Wireless LAN
	Soft blocked: yes
	Hard blocked: no
1: hp-bluetooth: Bluetooth
	Soft blocked: no
	Hard blocked: no
2: phy0: Wireless LAN
	Soft blocked: yes
	Hard blocked: yes
5: hci0: Bluetooth
	Soft blocked: no
	Hard blocked: no
$ 
$ 
$ iwconfig
lo        no wireless extensions.

wlan0     IEEE 802.11abgn  ESSID:off/any  
          Mode:Managed  Access Point: Not-Associated   Tx-Power=off   
          Retry  long limit:7   RTS thr:off   Fragment thr:off
          Power Management:off
          
eth0      no wireless extensions.

$ 
$ 

$ dmesg -T|egrep 'eth0|wlan0'
[all output here has time stamps > 2 days, so they shouldn't be related to the problem]

$ cat /var/lib/NetworkManager/NetworkManager.state

[main]
NetworkingEnabled=true
WirelessEnabled=false
WWANEnabled=true
$

[uncaspi]

Have you tried another cable?

[Bucky Ball]

Just out of curiousity, how old is this machine?

[carwe]

The machine is three years old.

No, I haven't tried another cable and I can't exchange it easily. But since a reboot helps, I wouldn't suspect the cable.