[CentOS] Physically moving a mail server vs. cached DNS

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. 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.