Expire

[Cricket Liu]

> From DNS and BIND p.90
> 
> expire
> ... Expiring the data means the slave stops giving out answers about the 
> data because the data are too old to be useful...
> 
> Two questions.
> 
> 1) Does the slave actually delete the data from its zone file
>    or just stops answering?

It begins to answer queries for records in that zone with a
SERVFAIL response code.  It doesn't delete any backup
zone data file it may have.

> 2) If the slave is restarted, and it doesn't delete the data, does
>    it answer queries for another Expire seconds?

No.  When the slave loads the backup zone data file, it can
tell from the file's modification time that the zone is still
expired.

cricket