[lxc-users] IPv6: Neighbour table overflow

[Tamas Papp]

On 02/18/2014 05:56 PM, Serge Hallyn wrote:
> Quoting Tamas Papp (tompos at martos.bme.hu):
>> hi All,
>>
>> I spent the whole day with debugging a weird network issue. On our
>> network there were packet losses, ping timeout and everything you can image.
>> I was sure, there is a loop, or faulty switch, but wasn't able really
>> identify the root. Sometime it was better, then the packet losses came
>> back after a while (last time after 5 hours...).
>>
>> Then I looked into syslog on one of servers and I saw many messages like
>> this:
>>
>> [772718.275810] IPv6: Neighbour table overflow
> http://cosu.ro/blog/2011/09/26/ipv6-neighbour-table-overflow/ makes it
> sound like those are just magic values, and suggests raising them
> without looking into why (which I'm not saying I agree with :)
>
> http://www.arcweb.ro/blog/2011/12/13/neighbour-table-overflow-debug-ipv4-and-ipv6/
> suggests blaming "occasional big spike of IPv6 ARP requests".  Which
> could be just an accident...  or could be some sort of attack.
>
> ...
>
>> The system was running without any glitch for months.
>> Any idea?
> I'm ashamed to admit I *still* haven't dived into the ipv6
> pool.  The msgs mean nothing to me.  Maybe this rings a bell for
> Stéphane?
>
> Anyway if you don't actually use ipv6, then certainly disabling
> it seems the safer option.  I prefer to disable code I'm not using.

Today the saga was continued.
Finally it turned out, that the root of the problems are faulty Gbic
devices or something like that.
However we aren't sure yet:/

Thanks!

tamas