Somewhat weird net behavior

[Robert Watson]

On Sat, 21 Oct 2006, Milan Obuch wrote:

> On Saturday 21 October 2006 17:28, Robert Watson wrote:
>> On Sat, 21 Oct 2006, Milan Obuch wrote:
>>> I know this is really minimum information here, but I need just an idea
>>> what to look for. It is strange for me - is it some memory leak? How
>>> could it be cleared with simple ifconfig up? Did anyone seen something
>>> similar?
>>
>> It is pretty minimal information :-).
>
> Agreed. I need some help in my investigation. I have no ide what to look 
> for.

FYI, I couldn't deliver e-mail to your e-mail address, but I guess you got it 
through the list.

>> ifconfig down / up will cause the device driver to be reset, the link to be 
>> re-negotiated, etc.  The buffer full error from ping means that the 
>> outbound interface queue has filled, and if the error doesn't go away, it 
>> means it's likely wedged (no longer being processed).  This could reflect a 
>> bug in the device driver, a problem with the switch, etc.  In the "wedged" 
>> state, what does ifconfig report about link negotiation?  When you reset 
>> the interface, does the negotiated link type change?
>
> I did only ifconfig up, not down/up sequence. That's a bit weird for me. 
> Anyway, on next ocasion, I will do ifconfig before/after ifconfig up. Could 
> there be some interesting information in some netstat output too? It happens 
> once - twice a week, so I would rather be a bit prepared beforehand.

The output of "ifconfig" with no arguments is probably a useful start.  That 
will tell us about link negotiation, the OACTIVE flag, and so on.

Robert N M Watson
Computer Laboratory
University of Cambridge