Repeated queries to the root-servers

[Bernhard Schmidt]

JINMEI Tatuya / 神明達哉 wrote:

>> Did I understand something wrong? Does anyone have an idea what could
>> cause this behaviour? 
> I cannot think of a scenario that would cause the described symptom,
> but I'd monitor the cache content while the 40 second test period
> (e.g., every 10 seconds) to see whether and how the .com referrals and
> glues are cached.  

Did that (with 1sec resolution). Method:

while true; do /usr/sbin/rndc dumpdb -all; cp
/var/lib/named/log/named_dump.db /tmp/dump.$(date +%s); sleep 1; done

Result: it just vanishes from one second to the other. Content just
before it is gone (1173718895):

com.                    172798  NS      a.gtld-servers.net.
                        172798  NS      b.gtld-servers.net.
                        172798  NS      c.gtld-servers.net.
                        172798  NS      d.gtld-servers.net.
                        172798  NS      e.gtld-servers.net.
                        172798  NS      f.gtld-servers.net.
                        172798  NS      g.gtld-servers.net.
                        172798  NS      h.gtld-servers.net.
                        172798  NS      i.gtld-servers.net.
                        172798  NS      j.gtld-servers.net.
                        172798  NS      k.gtld-servers.net.
                        172798  NS      l.gtld-servers.net.
                        172798  NS      m.gtld-servers.net.

grep reveals:
dump.1173718894:com.      172799  NS      a.gtld-servers.net.
dump.1173718895:com.      172798  NS      a.gtld-servers.net.
dump.1173718963:com.      172730  NS      a.gtld-servers.net.

so .com glue is only in three of ~60 dumps, but the TTL is increasing,
so dumpdb seems to be broken. dig -t ns com @127.0.0.1 shows that the NS
record is always in the cache (decreasing TTL), but it does not appear
in the dump.

Anything I'm doing wrong regarding rndc syntax?

Regards,
Bernhard

-- 
Bernhard Schmidt                               Netzplanung / IPv6
Leibniz-Rechenzentrum der Bayerischen Akademie der Wissenschaften
Boltzmannstr. 1                     D-85748 Garching bei Muenchen
Tel: +49 89 35831-7885         Raum I.2.071        schmidt at lrz.de