Why is $TTL required for the root hints?

[Roy Arends]

On Sun, 23 Sep 2001, Jesper Dybdal wrote:

> I have just upgraded from BIND 8.2.3 to 9.2.0rc3.
>
> I was surprised to see that BIND 9 insists on my having a $TTL in the root
> hints file.
>
> What is the meaning - if any - of the TTL value for the root hints?

Every record BIND caches will need to have a TTL value as is required by
rfc1035.

So, in general, at least once there must be a TTL

either

1) a $TTL directive, or
2) the first record has a TTL value, or
3) a SOA record exists (not required) with no TTL from where the MINIMUM
   is used

ad1: a SOA record is not required in the root-hints file.
ad2: copying SOA MINUMUM value only happens if a SOA exists and NO OTHER
     TTL or $TTL directive is specified.
ad3: if no roots/root-hints are specified, BIND 9 will default to the
     build in root-hints.

Regards

Roy Arends
Nominum

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