nslookup, dig, and host when name server is down

[Denys Vlasenko]

On Monday 13 April 2009 00:34, Gilles Espinasse wrote:
> > Sound like the behaviour I need is not achievable with dnsmasq too.
> >
> > My desired behaviour is this: Cache whatever successful queries.
> > When clients make queries, reply with cache entry if there is one,
> > but asynchronously make an attempt to query upstream.  If successful,
> > update cache. If fail, do nothing.
> >
> dont try to re-invent what exist
> dnsmasq should work for your need

Does it keep cached data (and for how long) when no DNS server answers.
> 
> > This gives an absolutely responsive dns cache behaviour which
> > does not slow down or block the clients.
> >
> When name server is down, don't try to use dig, nslookup or whatever
> program.
> Fix the reason why the name server is down.

Sometimes this is beyond user's contorl.

> This is not for nothing that you usually have 2 name server adresses.
> The switch is made by dnsmasq (tranparently except the little delay related
> to the first server timeout and the new election)

--
vda