FW: Periodic lookup failures

[Tony Davis]

Dear bind experts,
 
For a month or so now we've been having an intermittent problem whereby
one of our DNS servers (not always the same one) will fail to resolve
external addresses. We've tried using both forwarders and having a
db.cache file so the root servers are queried and it's made no
difference. When the problem occurs the lookups timeout.
 
Initially we were using bind 8.3.4 but I tried upgrading to 8.4.6 in
case it was some kind of bug. This is running on Solaris 8.
 
On the face of it the problem appears to be a DNS cache issue as when
named is restarted, everything springs back to life. Also, one time when
we were investigating the problem, the cache cleanup routine ran and DNS
started working again. However, when I snooped the network interface
during the problem, queries appeared to be sent out but I couldn't see
any reply packets. All very strange.
 
I've been trying to think what the problem may be, an invalid entry in
the cache perhaps? I was also wondering whether it may be some kind of
memory issue although there's always plenty of free memory.
 
Anyway, if anyone has any suggestions, they would be most welcome.
 
Thanks
 
Tony 

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