Moving DNS out of non-cooperative provider

Cathy Almond cathya at
Thu Jun 21 10:38:59 UTC 2012

On 19/06/12 11:18, Alexander Gurvitz wrote:
>> 3282.   [bug]           Restrict the TTL of NS RRset to no more than that
>>                        of the old NS RRset when replacing it.
>>                        [RT #27792] [RT #27884]
> Just to clarify - does this rule applies also while replacing parent NS
> records
> with (more credible) child NS records ?
> If yes - child TTL larger than 48 hours (i.e. for .COM) is always
> disregarded.
> If not - ghost domains issue is not solved.
> (I'm sorry for being annoying.)

No - you're not!

In answer to your first question:

> "TTL of the old NS RRset" here means the current "remaining" TTL,
> or the original TTL value as received with the authoritative answer ?

This means the current "remaining" TTL - otherwise it's not going to
achieve the desired result.

And yes - it does also apply when replacing parent NS records with child
NS records - with the limitation that you already observed, that a child
TTL that is larger than the TTL in the parent is going to be disregarded.

Also - if in your example above, if the child NS records have a smaller
TTL than the currently 'counting down' cached and larger TTL from the
parent zone, then we'll use the smaller TTL of the child zone records
thereafter too - although I think this is more intuitive/obvious.


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