Two DNS lookups for a server but one fails

Ward, Martin Martin.Ward at colt.net
Mon Jan 5 14:58:56 CET 2009


Hi all,

I have a number of servers that run their own DNS service, each giving
out a single IP address. These DNS servers are monitored in bb-hosts
like this (names and Ips changed to protect the guilty):

1.2.3.4    dns1.server.com        # smtp
dns=a:smtp.server.com,ns:smtp.server.com

The issue is that this configuration performs two DNS lookups, one for
an NS record for smtp.server.com and one for and A record for
smtp.server.com. When run either the NS or the A record is returned but
not both. The one that fails shows the following in the web interface:

Service dns on mc20.lon.server.com is not OK : Service unavailable

*** DNS lookup of 'a:smtp.server.com' ***
Timeout (channel destroyed)

In this instance it was the A record that failed but in others it is the
NS record. I always get one of the queries back successfully, but not
both.

These were working fine until I upgraded to Xymon 4.2.2 so this looks
like the culprit. Any ideas or suggestions?

|\/|artin
--  
Martin W. Ward
TAC Network Systems Team Leader
COLT
Unit 12, Powergate Business Park
Volt Avenue, Park Royal, London
NW10 6PW, United Kingdom

Tel: + 44 (0)20 7863 5218   Internal: 8 441 5218
Fax: + 44 (0)20 7863 5610
Email: martin.ward at colt.net 
www.colt.net

Data | Voice | Managed Services


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