[Xymon] Purple storm

[Jeremy Laidman]

On Wed, Mar 21, 2012 at 9:11 AM, Jamison Maxwell
<jamison at newasterisk.com> wrote:
> What order are the name servers in /etc/resolv.conf?  I was playing with Debian this weekend and for some reason, no matter what I did it would not use any other name server than the first one in the list except for dig and nslookups, but not for regular queries.

That's all normal behaviour.  The standard resolver library on Linux
will only use second and third entries in resolv.conf when the first
one is unavailable for 5 seconds (see "man resolv").

The dig, nslookup and host programs don't use the resolver library,
and instead use their own in-built resolver that behaves differently
to the standard resolver - but still uses the "nameserver" entries
from resolv.conf.  For this reason, when diagnosing DNS problems with
applications, using dig/nslookup can give you results different to the
application you're testing; it's better to use things like "ping" or
"telnet" to do a lookup, as they use the same resolver library as most
other applications, including Xymon.