Nsupdate and TTL

[Evan Hunt]

On Wed, Apr 22, 2020 at 03:04:38PM -0600, @lbutlr via bind-users wrote:
> # nsupdate -k /path/to/key
> > zone example.com
> > ttl 3600
> > send
> > ^d
> 
> No errors, but no change in the TTL.

"ttl 3600" just means "from now on assume I mean ttl 3600 in all the
records I send". You didn't actually send an update, so nothing changed..

As far as I can recall, the only way to change a TTL in nsupdate is to
delete the whole RRset and then add it back in the same transaction:

> zone example.com
> ttl 3600
> update del example.com in a
> update add example.com in a 192.0.2.1
> update add example.com in a 192.0.2.2
> update add example.com in a 192.0.2.3
> send

-- 
Evan Hunt -- each at isc.org
Internet Systems Consortium, Inc.