On Sat, 2017-07-01 at 11:37 +0200, Nicolas Kovacs wrote:
Le 01/07/2017 à 11:00, Pete Biggs a écrit :
That is controlled by the TTL (time to live) entry. A DNS server must refresh it's cache within the TTL for the entry. Using the '-a' option to host will give you more information:
So I would have to use the -a option with the old DNS server, to know their TTL.
Yes, or use dig or something else that shows the TTL
I'm also wondering if some DNS server don't override the TTL and keep the information longer. I remember such a case where the DNS server of the french provider Orange kept a stale DNS information forever.
The TTL is part of the DNS record so no, they shouldn't override it, in the same way as they shouldn't override the A record or MX record. That doesn't mean that some providers don't do it "for operational reasons", but it's a stupid thing to do and will basically, literally, break the internet.
P.