Some confusion about DNS also backup MX records
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Thread: Some confusion about DNS also backup MX records

  1. #1
    Junior Member
    Join Date
    Jul 2014
    Posts
    1

    Some confusion about DNS also backup MX records

    I would like to do the incremental migration, but am not sure about the part in the instructions about DNS as this part of the instructions seems a bit incomplete ... i have set the ttl to 300 (NOTE that most servers on the web will probably ignore this setting and cache for at least 1h anyhow ) for all my domains but not sure what to set for MX records in my DNS server

    FYI source server will be mx1.myserver.ca and destination server will be mx2.myserver.ca

    i now have the following records on the mail server for source and destination machines

    mx1.myserver.ca. IN A x.x.x.131
    mx2.myserver.ca. IN A x.x.x.132

    and these on each of the domains that need to be transfered

    somedomain.com. IN MX 22 mx1.myserver.ca.
    somedomain.com. IN MX 100 mx2.myserver.ca

    however there is no mention in any doc that i can find about what/how to setup DNS records or if a backup MX isa plausible way to do migration without down time? as usual i am probably missing something obvious here and may not need or want backup MX records

    please advise! and thank you in advance

  2. #2
    Wise Guy Participant
    Join Date
    Apr 2011
    Posts
    34
    Hello c0mputerking, and welcome to the forum.
    Quote Originally Posted by c0mputerking View Post
    I would like to do the incremental migration, but am not sure about the part in the instructions about DNS as this part of the instructions seems a bit incomplete ... i have set the ttl to 300 (NOTE that most servers on the web will probably ignore this setting and cache for at least 1h anyhow ) for all my domains but not sure what to set for MX records in my DNS server

    FYI source server will be mx1.myserver.ca and destination server will be mx2.myserver.ca

    i now have the following records on the mail server for source and destination machines

    mx1.myserver.ca. IN A x.x.x.131
    mx2.myserver.ca. IN A x.x.x.132

    and these on each of the domains that need to be transfered

    somedomain.com. IN MX 22 mx1.myserver.ca.
    somedomain.com. IN MX 100 mx2.myserver.ca

    however there is no mention in any doc that i can find about what/how to setup DNS records or if a backup MX is a plausible way to do migration without down time? as usual i am probably missing something obvious here and may not need or want backup MX records

    please advise! and thank you in advance
    Well, the incremental migration guide does not delve into the DNS portion of a migration since it's something left to the expertise, and choice, of a mail server administrator.
    We find that a delay in the delivery of e-mail from outside is a given when migrating from one server to another, and lowering the TTL for the MX records mitigates that.
    Using a backup MX, on top of lowering the TTL, is another way to proceed, provided you block the incoming SMTP traffic to the target server before the migration, and to the source server after the migration.
    Alternatively, depending on the layout of your network, you could leave a single MX record with the new server after the migration, and activate a port forwarding redirecting the SMTP flow coming from outside towards the ip of the source server so that it actually reaches the target server, removing it once you are reasonably certain that the DNS change has been propagated.

    Let me know if the above clarifies the matter for you.

    Regards,
    Trantor
    ZeXtras Website # ZeXtras Wiki # ZeXtras Store

    ZeXtras System Administrator and Installer Guru

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