1 hour subdomain failures

[Mark_Andrews at isc.org]

	What are the SOA counter values for the zone in question?

	My bet is that expire is set at 1 hr and refresh is set
	at 2 hrs.  Expire should always be very much greater than 
	refresh.

	Mark

> 
> 	I've been tracking down a intermittent
> name server problem from a single caching DNS server.
> This caching DNS server will oscilate between
> being able to answer queries and not being able
> to answer the queries for hostnames in the subdomain.
> The oscillations are exactly two hours in total
> length (one hour it works, for the next hour
> it is broken).
> 	When I say it is broken I mean that when
> we send a query we never get a packet in reply.
> When I perform the query via tcp the socket closes
> right after the query.  (I've been modifying the
> code to dnsquery for these tests).
> 	We have been monitoring several caching
> name servers and this is the only server that has
> this problem!
> 	Some more details...  The ttl for the NS
> record for this subdomain is 1 hour.  The ttl for
> hosts in this subdomain is 6 minutes.
> 	Could it be that when the NS record
> expires (after 1 hour) the caching server waits
> for an hour before it contacts the authoritative server 
> again?  Does anyone know of a name server implementation
> the exhibits this behavior?  (i.e. a 2 hour limit
> before recontacting an authoritative name server?)
> 
> 		-John
> 
> -- 
> John Studarus <studarus at one.net>
> 
> 
--
Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org