Querying locally on a nameserver - odd behavior
blrmaani at gmail.com
Mon Oct 3 02:41:50 UTC 2016
On Wednesday, September 21, 2016 at 8:10:16 AM UTC-7, Graham Clinch wrote:
> >>> I have a DNS server (which is both forwarder and authoritative NS) and I see this odd behavior locally on the host:
> >>> dig @localhost <name> # returns immediately with right response
> >>> dig @<host-local-ip-on-eth0> <name> # returns sometimes, timesout most of the time
> > [...]
> > during this behavior, I saw lots of UDP packet loss on the host:
> > netstat -s | egrep -A4 "Udp:"
> > ...
> > ..
> > I tried similar local queries when traffic reduced (and when UDP pkt loss was zero) and both local queries succeeded.
> Which version of Bind are you running? This sounds like an issue I've
> seen with prefetch in 9.10 before 9.10.4.
BIND 9.8.x. This behavior is seen when there are flood of NXDOMAIN queries sent to our nameserver running BIND 9.8.x
As a short-term fix, we have added our nameservers behind a netscalar VIP and provided additional capacity to hadoop applications. I hope I'll have some time soon to get to the bottom of this problem (or just upgrade to BIND 9.10.x ? :) )
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