having slave not time out

[Jeremy C. Reed]

On Fri, 18 Apr 2008, david brett wrote:

> I am looking for a solution where the slave DNS will not time out if the 
> master is unreachable for too long.  I don't want to increase the time 
> out for long periods, because this would have cache DNS keep the record 
> for too long.

The caching time-to-live (defined by $TTL or TTL field) and the zones' 
refresh/retry/expire times (defined in SOA) are not related.

If you really don't want the slave to "expire" set the SOA "expire" to a 
large 32-bit value that will never get reached. Note that RFC 1912 
suggests 2 to 4 weeks (1209600 to 2419200 seconds).

Or increase the refresh interval so it won't attempt to renew for a long 
time (and let master use "notify" to let slave know).

> Essentially I am trying create a permanent backup running which is 
> updated from the master automatically, by notification.

The notify option is enabled as yes by default.

Note that normally the real goal is for the slave to have accurate, valid 
data and not old data.