Re: shorten cache ttl?

>>>>> "Marten" == Marten Lehmann <lehmann@cnm.de> writes:

Marten> Bind seems to remember the "I didn't find such a record at
Marten> the authoritative dns" for some time and does not ask the
Marten> authoritative nameserver again the second time, while
Marten> djbdns does. I guess BIND uses sort of TTL, but whats the
Marten> TTL of a non existing record? But even existing entries
Marten> are cached to long (but maybe according to the TTL of the
Marten> authoritative nameserver). Can I overwrite the TTL of the
Marten> authoritative nameservers at my caching nameserver, so
Marten> that the records expire earlier?

BIND implements negative caching: "remember that the name/class/qtype
you asked for doesn't exist". How long it remembers those answers
depends on the data sent by authoritative server. It's usually the
value of the MINIMUM field of the SOA record for the zone enclosing
the name that was looked up. Read RFC2308.