[dns-operations] negative caching weirdness

[Robert Edmonds]

Matthew Pounsett wrote:
> On 22 April 2016 at 15:01, Daniel Stirnimann <daniel.stirnimann at switch.ch>
> wrote:
> 
> > >     Now, the only strange result left is if I look up the name using my
> > >     local resolver which returns 10800.
> > >
> > > Your local recursive server will give you the cache TTL, which is the
> > > amount of time remaining on the TTL, not the TTLs original value.
> >
> > I don't think this is the case. I get the same result if I flush the cache.
> >
> 
> Is it possible your recursive server implements a max TTL configuration
> value that is set to 10800?
> 
> I'm curious what recursive server you're using, if the TTL it reports
> doesn't decrement as time passes.

Probably BIND, where the default 'max-ncache-ttl' setting is 10800. The
Unbound equivalent is 'cache-max-negative-ttl' and its default is 3600.

-- 
Robert Edmonds