Mysterious load increase, BIND 8.2.2,p5

cschen at cc.nctu.edu.tw cschen at cc.nctu.edu.tw
Fri Apr 21 08:56:18 UTC 2000


Mark W. Manley <mwm3q at calvin.acc.virginia.edu> wrote:
> The only somewhat plausible explanation that I have is that we were
> having problems with another Internet site that had set its TTL values
> on their A records to zero.  They called and complained to us about our
> nameservers beating up theirs for answers.  After explaining to them
> what a TTL does, they corrected the problem.  Magically, we have not
> had another load spike (we experienced four different sets of them over
> the course of the day, making our nameservers almost unusable).  In
> the O'Reilly DNS and BIND book, there is some mention of the behavior
> with TTL's of 0 for BIND 4, but none for BIND 8.  Could that be the
> culprit?

We'd encountered similar situations about 2 weeks ago on one of
our DNS server running BIND 8.2.2-P5.  (OS: Solaris 2.5.1)
- The server runs as DNS forwarder for many local DNS servers.

We'd dumped the memory snapshot of the named process by issuing
 "kill -USR1 `cat /etc/named.pid` "

And I found tons of continuous DNS queries in short interval about
some other entries with TTL set to zero.  It seems that the site 
with the zero TTL entries runs DHCP (or something of the kind).



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