How to mangage change of mailserver without mail loss

Barry Margolin barmar at genuity.net
Thu May 4 01:48:47 UTC 2000


In article <8eqf04$8du$1 at lure.pipex.net>, pipex <aa at aaa.aa> wrote:
>What happens to mails sent to a domain e.g. someone at adomain.com when the
>Internic DNS entry for the domain and the MX record is changed to other IP
>addresses.
>
>As far as I know DNS entries have a life between 1-7 days. So does it mean

Root/GTLD delegation records have 2-day TTLs.  Other DNS entries have TTLs
specified by the administrator of the domain.

>mail would go to the old IP address until the DNS change is propagated to
>all nameservers in the world?

Servers that have the old entry cached will continue trying to send to the
old IP address.

>Is is possible to make changes to the MX record before the IP switch so that
>mail starts going to the new destination.

A common solution is to install two MX records before the switch:

adomain.com MX 10 newserver
            MX 20 oldserver

Until the new server is ready, attempts to connect to it will fail, so
senders will fail over to the oldserver.  After the switch, connections to
newserver will succeed.  Then you can get rid of the MX 20 line.

-- 
Barry Margolin, barmar at genuity.net
Genuity, Burlington, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.



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