[olug] DNS: dropping to secondary when primary doesn't respond

[Kevin]

DNS uses UDP, so the clock starts as soon as the request packet leaves
the requesting computer. If the server doesn't respond in the time
allotted(5 seconds?), then it moves on to step 2. I'm not sure where,
but I think it tries 4 times before calling that DNS server dead and
moving on to the next server.

On 7/28/07, Dave Thacker <dthacker9 at cox.net> wrote:
> I have three DNS servers providing internal (inside the firewall) DNS.   All
> servers on the network have entries by ip address for these three servers
> in /etc/resolv.conf.   My question is:
>
> 1) If the first server in the list can't be reached at all, how fast does the
> request time out and move to the second server.
>
> 2)If the first server will accept the request, but is slow in providing an
> answer, how fast does the request time out and move to the second server?
>
> 3)  Is that interval tunable?