<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; charset=us-ascii"> <META content="MSHTML 6.00.2900.2963" name=GENERATOR></HEAD> <BODY> <DIV dir=ltr align=left>We dealt with this by installing a local caching-only nameserver on the Nagios host itself. This also took a lot of the load off of the main nameservers. So, resolv.conf was set to use 127.0.0.1 by default and have our normal name servers as secondaries. A nice sideeffect was that it vastly sped up the name resolution.</DIV> <DIV dir=ltr align=left> </DIV> <DIV dir=ltr align=left>Steve</DIV> <DIV> </DIV> -- Steve Shipway ITSS, University of Auckland (09) 3737 599 x 86487 s.shipway@auckland.ac.nz <DIV> </DIV> <BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px solid; MARGIN-RIGHT: 0px"> <DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left> <HR tabIndex=-1> From: nagios-users-bounces@lists.sourceforge.net [mailto:nagios-users-bounces@lists.sourceforge.net] On Behalf Of stucky Sent: Friday, 10 November 2006 6:57 a.m. To: Az Cc: nagios Subject: Re: [Nagios-users] timeouts when using secondary dns </DIV> <DIV></DIV>Yey !! That totally did it. Thx AZ I hadn't even considered messing with the resolver cuz I was sure it was a nagios issue so I had to fix nagios. If that wasn't a text book example of how well mailinglists can work then I don't know what is... thx <DIV>On 11/7/06, Az <<A href="mailto:az@whoever.org">az@whoever.org</A>> wrote: <BLOCKQUOTE class=gmail_quote style="PADDING-LEFT: 1ex; MARGIN: 0pt 0pt 0pt 0.8ex; BORDER-LEFT: rgb(204,204,204) 1px solid">stucky wrote: > I use the check_by_ssh plugin for most of my stuff and I noticed that > if the primary nameserver is unavailable nagios starts freaking out. > All of a sudden all plugins time out. I tested it using the 'host' > command and it only takes about 1 second longer to lookup hosts using > the secondary nameserver. > The default timeout for check_by_ssh is 10 seconds. I cranked it up to > 30 and still I get timeouts. I'm not sure I understand that one. > Has anyone else seen this. We had a similar issue in that our primary DNS was doing strange things, and it quite often took 5 or even 10 seconds to perform a DNS lookup. What we were seeing was 70% of service checks (and subsequently host checks) failing by timing out. The key was the multiple of 5 seconds. The resolver timeout on, say, RHEL3 is based on RES_TIMEOUT in resolv.h... which was 5 seconds. We added the following to our resolv.conf , and found the problems went away: options timeout:2 rotate This sets the timeout for waiting for a reply to 2 seconds, and tells the resolve to rotate through your 'nameserver' entries rather than always hitting #1, then #2, etc. Cheers. </BLOCKQUOTE></DIV> -- stucky </BLOCKQUOTE></BODY></HTML>