Wednesday, August 07, 2013, 14:49
Solution ID: 00000212
What is the Best Practice for changing mail server DNS records?
Changing DNS records involves a propagation delay that may be as long as 48 hours. After changing your MX records in DNS you cannot tell how long it will be before mail servers will become aware of your new MX record and new mail server. In this 48 hour time span you can expect e-mail to be sent to both the old and new records.
Further, this process can result in downtime if there are problems with the mail server migration. Consider a situation where you are forced to fall back to the old mail server and the new MX records have already propagated through DNS. Servers may be unable to reach your old mail server.
The following procedure allows you to perform a discreet, clean cut over with no loss of e-mail and allows for falling back to the old server if there is an issue with the migration.
Clean Mail Server Cutover Procedure:
1) Ensure both mail servers are operational.
2) Turn off SMTP for the new mail server and add the new MX record in DNS.
2) Wait 48 hours.
3) Turn on SMTP for the new mail server and turn off SMTP for the old mail server.
4) Test. If there are migration issues simply reverse step 3.
5) Remove the old MX record in DNS.
Tags: dns, configure, mx, delay, propogation
Link to this article: kb/changing_dns_records
Updated: Wednesday, August 07, 2013, 14:49
-- David Rutherford
Last modified: 2013-08-07, 14:49
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