System Drops Network Connection **SOLVED Please read solution**

[Jay Ridgley]

On 12/25/2013 06:58 AM, Jay Ridgley wrote:
> On 12/24/2013 08:20 AM, Jay Ridgley wrote:
>> On 12/24/2013 03:22 AM, Colin Law wrote:
>>> On 24 December 2013 09:17, Jay Ridgley <jridgley2 at austin.rr.com> wrote:
>>>> Folks,
>>>>
>>>> Recently one of my systems started dropping the connection to my network. If
>>>> I reboot the system it is up for a while as long as no one is doing anything
>>>> on it(no logins and no printing) but it will drop the connection after a
>>>> time. My gut feel is that Network Manager is causing the problem but I do
>>>> not know where to look to find the problem.
>>>>
>>>> There has been no changes made for the configuration files yet this happens.
>>>>
>>>> I have found some information with Google about this type of problem but I
>>>> have not been able to find a solution.
>>>>
>>>> I use a static wired connection to my network.
>>>>
>>>> System is running Ubuntu 12.04.3 LTS (GNU/Linux 3.2.0-57-generic i686) all
>>>> updates have been applied.
>>>>
>>>> I have two systems that are configured in the same manner one has no
>>>> problems the other does. Any ideas?
>>>
>>> Anything in /var/log/syslog?
>>
>> There are several entries for Network Manager reporting Unmanaged Device found
>>>
>>> When you say it goes down, do you mean it says it is disconnected or
>>> just is not working?
>>
>> It remains working, however, there is no connection to the network. Can not ping
>> yahoo.com for example.
>>
>>> What happens if you unplug the cable and put it back?
>>>
>
> Colin,
>
> Merry Christmas!
>
> Sorry to take so long
>
>> Have not tried that, yet
>
> This morning I unplugged the cat 5 cable and plugged it back in and the system
> connected to the network. I was also able to ping yahoo.com & 98.139.183.24 (as
> Paul Cartwright suggested - I do NOT think it is a DNS problem) (see below)
>
> Yesterday I monitored the system after I had reinstalled Network Manager using
> synaptic and rebooted the system.
>
> I used an ssh connection from another system and started running:
> tail -f /var/log/syslog
>
> That was working fine on an idle system until:
>
> Dec 25 00:17:01 ursa CRON[2802]: (root) CMD (   cd / && run-parts --report
> /etc/cron.hourly)
> Write failed: Broken pipe
>
> I was asleep and did not see the results until I got up this morning...
> I was able to restart the ssh connection successfully.
>
> /var/log/syslog continued to record events just like that shown above (cron
> entries) until about 06:14 then there are several entries. It shows the NIC
> being unplugged and the network restarting...
>
> I will continue to monitor...
>
> Ideas?
>
> Cheers,
> Jay
>

Folks, I said I would continue to monitor this situation...

The ROOT cause was a was a bad network connection AT THE WALL. I isolated the 
problem by using another spigot (in the same room) with a longer cable. It 
worked fine for several days. I asked myself if the cable I was using originally 
was bad, and tried the new cable with the original connection... yep down it went!

So I replaced the wall plug with a new one and restored the original cable. NO 
MORE PROBLEMS!

Cheers,
Jay

-- 


Jay Ridgley
jridgley2 at austin.rr.com
Registered Linux User ID - 9115
https://linuxcounter.net/cert/9115.png
Registered Ubuntu User ID - 23320