How FreeBSD Handles a DNS that is Down

[RW]

On Thu, 21 Oct 2010 06:22:15 -0500
Martin McCormick <martin at dc.cis.okstate.edu> wrote:

> 	Last night, I had to take down our primary DNS for
> maintenance and lots of systems began having trouble of various
> kinds.
> 
> 	While I expected the FreeBSD system I was on to hang for
> a couple of seconds and then start using the second DNS, it
> basically froze while some Linux boxes also began exhibiting
> similar behavior.
> 
> 	I finally manually changed the resolv.conf on the system
> I was using to force the slave DNS to be first in the list and
> that helped, but loosing the primary DNS was not the slight
> slowdown one might expect. It was a full-blown outage.

It works for me. The rules aren't 100% consistent, because some
software parses resolv.conf, or uses configured servers, and then goes
direct to the nameserver. 

Have you checked your firewall? Or maybe there is some difference
between the two server.