Dynamic DNS record expiration, journal file behavior

[/dev/rob0]

On Wednesday 2005-August-31 11:31, Joe wrote:
> I understand that when a DDNS update is sent the entry is placed in a
> journal file (.jnl) which is not added to the zone file for up to 15
> minutes.
> (http://www.bind9.net/manual/bind/9.3.1/Bv9ARM.ch04.html#journal).
>
> Is there a way to shorten this update time? I would perfer if the
> updates are next to immediate. I realize the number of

The updates ARE immediate. Try it yourself. Change or add a record and 
resolve it. It's there, even out to remote slaves, faster than you can 
type the host(1) or dig(1) command to resolve it.

> Also, I know that when the TTL value in a DDNS record expires a
> device will query the server for an updated record... but what
> happens on the server side to a DDNS record that has an expired TTL?
> Is the record dropped from the zone or is it kept there until the
> record is deleted or updated by the DDNS client?

The TTL only applies to the caching of the RR. Updates to the zone are 
permanent unless/until changed. Just like "regular" DNS.

> My goal is to have DDNS updates appear in the zone almost immediately
> and have a very low TTL to ensure querying entities always have the
> latest IP information. This is a network running internally.

Congratulations! You have it.
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