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    How to Load Balance Incoming Email or have a backup Public IP


    Hi everyone,

    How to add another Public IP on my mail server to have a back up or load balance incoming Email.
    Can I define multiple A records with the same mail server name and add another MX record? Do I need also the second IP have also rDNS?

    my current setup:

    A records:
    A mail.example.com 111.22.123.456

    MX record:

    example.com MX 10 mail.example.com

    Appreciate your help..
    Thanks!
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  3. Lazy Moderator
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    The best method is with multiple MX records to prioritize mail servers.
    Code:
    A mail.example.com 1.1.1.1
    A secondary-mail.example.com 1.1.1.2
    A backup-mail.example.com 1.1.1.3
    Code:
    example.com MX 10 mail.example.com
    example.com MX 10 secondary-mail.example.com
    example.com MX 20 backup-mail.example.com
    The alternative is multiple A records to do load balancing over DNS.
    Code:
    A mail.example.com 1.1.1.1
    A mail.example.com 1.1.1.2
    A mail.example.com 1.1.1.3
    Code:
    example.com MX 10 mail.example.com
    I don't know why you're asking about a second IP address: obviously you must have more than one for any of this to matter.

    Comments on this post

    • odiecoranes agrees
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    Hi requinix,

    Thanks for the inputs..

    since i only have one mail server I'll go for "multiple A records to do load balance over DNS"

    I don't know why you're asking about a second IP address: obviously you must have more than one for any of this to matter.
    what i'm asking is, it is required that my second IP have rDNS on my ISP provider?

    Thanks!
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  7. Lazy Moderator
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    The whole point of load balancing is what to do with multiple servers. If you only have one server then it is all meaningless.

    Don't do anything. One MX record. One A record.
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    There are a whole lot of backup email server services available for a couple bucks a month.
    ======
    Doug G
    ======
    I've never been able to appreciate the sublime arrogance of folks who feel they were put on earth just to save other folks from themselves .." - Donald Hamilton
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    Originally Posted by requinix
    The whole point of load balancing is what to do with multiple servers. If you only have one server then it is all meaningless.

    Don't do anything. One MX record. One A record.
    Hi requinix,

    Currently we have only one mail server and I'm currently testing zimbra multi server installation to migrate our existing Mail server. We are having a frequent downtime with our ISP so im thinking of to use another backup ISP on this single server While waiting for our new hardware and done zimbra testing.

    Does this become an issue having 2 MX or DNS record pointing to one mail server?

    Thanks!
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    If you only have one functioning mail server then multiple records are pointless. But no, it would not cause any problems.
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    But we can use the 2nd ISP as a backup for now in case of the first one down..
    Thank You,
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    Then you have more than one functioning mail server and thus multiple records will be useful.

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