Updated Ubuntu 9.10 and eth0 disappeared

[saphil]

I did an weekly update through aptitude, and it asked for a restart.
after the restart, there was no ethernet available.
ifconfig brought absolutely nothing, as though the card was no longer present
This is on an old dell tower.
How do I find out what happened. I don't know how to find out what was in the update.

[Kieren]

Try:

ifconfig -a

[reed9]

Should be a log at /var/log/dpkg.log that will show you what was updated.

Post

lspci -vnn
lsmod
dmesg | grep eth

[coopstah13]

A lot of people seem to be having this problem recently, I wonder if ubuntu developers released a bad update, there are a lot of posts recently on here about network connections not working after an update.

[saphil]

maybe.
I turned off the machine since it was off the network anyway. Turned it back on today, and the card is back up.
I had already done 2 reboots before I bothered you with the issue, and they had done nothing. There was no other updates done that could have fixed the issue.

[Kieren]

Could you have knocked out the network cable?

[saphil]

The symptom was that ifconfig gave absolutely no response.
Even if I knocked out the cable, wouldn't ifconfig have shown the loopback?

it was like:

wolf@telcontar:~$ ifconfig 
wolf@telcontar:~$

Now if eth0 is downed, the ifconfig still shows both the loopback and the NIC:

wolf@telcontar:~$ ifconfig
eth0      Link encap:Ethernet  HWaddr 00:1e:68:80:14:21                                                 
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:286776 errors:0 dropped:0 overruns:0 frame:0                                       
          TX packets:170502 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:333730621 (333.7 MB)  TX bytes:21901506 (21.9 MB)
          Interrupt:29 Base address:0xe000

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:6782 errors:0 dropped:0 overruns:0 frame:0
          TX packets:6782 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:475844 (475.8 KB)  TX bytes:475844 (475.8 KB)

wolf@telcontar:~$

It is a built-in ethernet card, so it can't shake loose. I am starting to think there is a hardware problem somewhere.

[Kieren]

If there is no cable in the card ifconfig can sometimes not list the device. You can get it to list all devices (connected or not) by using -a:

ifconfig -a