Query on DNS Bind cache setting

[Barry Margolin]

In article <d6f3t5$2pnn$1 at sf1.isc.org>,
 "Sabat Gangadhar" <sgangadhar at novell.com> wrote:

> Hi All,
> 
>          In DNS bind, two clean the cache, 2 types of cache setting are
> there. One is at zone level by default 24hr, and another at server level

No, it's actually at the record level, but when configuring the 
authoritative server you can set per-zone defaults.  The only zone-level 
TTL is the negative cache TTL, which comes from the zone's SOA record.

> such as max-cache-ttl, max-ncache-ttl and cleaning-interval.
> Which level setting is effective if both options are set?
> Thanks in advance.

The max-XXX-ttl server settings are just a maximum.  A record's TTL will 
be used unless it's longer than the max-XXX-ttl, in which case the 
latter will be used instead.

Cleaning-interval has no effect on any of this.  It just specifies how 
often named will search through the cache looking for entries that have 
timed out.  But if a record is looked up and it has timed out, it will 
be deleted immediate even if the cleaning interval hasn't run out.

-- 
Barry Margolin, barmar at alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***