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

Sat Jul 1 20:37:35 UTC 2017
Pete Biggs <pete at biggs.org.uk>

> You should check to see if your old SOA is still showing themselves
> as authoritative for your domain. If they are, then anyone who uses
> their nameservers will still get the old record(s) for your domain.
> If they are still showing themselves as authoritative (which I think
> is the case) you will want to contact them to have them drop your
> domain from their server(s), or at least get your host records
> updated to point to your new servers. 
Yes, that does seem to be the case.

Nicolas, if you make the query directly from the nfrance.com servers
you can see what we mean:

    $ host -a microlinux.fr ns.nfrance.com
    Trying "microlinux.fr"
    Using domain server:
    Name: ns.nfrance.com

    ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 2088
    ;; flags: qr aa rd; QUERY: 1, ANSWER: 6, AUTHORITY: 0, ADDITIONAL: 7

    ;microlinux.fr.    	    	    	    IN    	    ANY

    microlinux.fr.    	    	    9600    	    IN    	    SOA    	    romeo.hebergement-discount.com. dns.nfrance.com. 2012081401 43200 1800 864000 9600
    microlinux.fr.    	    	    9600    	    IN    	    NS    	    ns2.slconseil.com.
    microlinux.fr.    	    	    9600    	    IN    	    NS    	    ns1.slconseil.com.
    microlinux.fr.    	    	    9600    	    IN    	    NS    	    ns3.slconseil.com.
    microlinux.fr.    	    	    9600    	    IN    	    MX    	    10 mx1.nfrance.com.
    microlinux.fr.    	    	    9600    	    IN    	    A

    ns1.slconseil.com.    	    432000    	    IN    	    A
    ns1.slconseil.com.    	    432000    	    IN    	    AAAA    	    2a00:1a60:22e0:4d00::1
    ns2.slconseil.com.    	    432000    	    IN    	    A
    ns2.slconseil.com.    	    432000    	    IN    	    AAAA    	    2a00:1a60:21e4:8100::1
    ns3.slconseil.com.    	    432000    	    IN    	    A
    mx1.nfrance.com.    	    60    	    IN    	    A
    mx1.nfrance.com.    	    60    	    IN    	    A

So nfrance.com still claim SOA on your domain. At least they have a
relatively short TTL on it of 9600s so things will correct themselves
quite quickly once they drop the domain.