Maintained by: NLnet Labs

[Unbound-users] No answers from unbound occasionally

Attila Nagy
Fri May 29 17:08:43 CEST 2009


Hello,

FreeBSD 7-STABLE, unbound r1584, single threaded.

It seems that occasionally it does not answer (or just doesn't receive, 
I don't know) the queries.

With tcpdump it seems that the machine gets the query, but there is no 
answer from unbound.
Its statistics counters seems OK, there is no full queue, or drops 
according to that.

However netstat shows a high amount of "dropped due to no socket" cases:
netstat -s -p udp
udp:
    17958542831 datagrams received
    0 with incomplete header
    0 with bad data length field
    25928 with bad checksum
    16209476 with no checksum
    46927070 dropped due to no socket
    33 broadcast/multicast datagrams undelivered
    72146984 dropped due to full socket buffers
    0 not for hashed pcb
    17839442816 delivered
    18155004206 datagrams output
    0 times multicast source filter matched

I've already tried to raise the related sysctls, without any effects.

Any ideas?

Would it be possible to selectively enable verbose logging? I can 
reproduce the no answer case in about an hour with a query tester 
sending about 100 queries per second, but I can't enable the verbose 
log, because it would kill the machine.

Thanks,