IPv6-related (?) Bind issue

[Hannes Frederic Sowa]

On Thu, Mar 06, 2014 at 11:00:28AM +0200, Yannis Nikolopoulos wrote:
> we've encountered a weird problem on our dual-stack (anycast) resolvers 
> and I'm wondering if anyone else has experienced anything similar. 
> Basically, we're getting many SERVFAIL responses for domains not in 
> cache. The weird part: if the domain does not exist in the cache, a 
> SERVFAIL response is produced (not all of the times) without the 
> resolver querying the auth NS (no outgoing communication is attempted).

If you really thing this might be a kernel issue, please record the number of
failed syscalls during the time this problem exists: perf script
failed-syscalls-by-pid -p or strace -c.

Further please record network packets drop in the stack via perf script
net_dropmonitor.

This might give a hint.

Thanks,

  Hannes