Update Slave from a Dynamic DNS of Master

[Cricket Liu]

> Might be quick question... I might be lost...
> 
> When I update the Master DNS by nsupdate it isn't updating the
> slave... The serial number is never updated so I don't know how
> the slave would ever realize to get the IXFR.

After receiving a successful dynamic update, the primary master
name server should increment the zone's serial number and, if it's
using NOTIFY, send notification to the zone's slaves.  Some BIND
8 name servers "throttled" this process somewhat, though:  they'd
wait until they received a certain number of dynamic updates (100
comes to mind) or a certain amount of time passed (five minutes)
before incrementing the serial number and triggering the notify.

You might want to make sure that the dynamic update is actually
successful (e.g., all prerequisites are satisfied) and that you're waiting
long enough for the primary master to increment the serial number and
send the notification (assuming you're using BIND 8).

cricket