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How to use Backup Mail Exchanger feature

Discussion in 'E-mail Discussions' started by sohot, Oct 18, 2009.

  1. sohot

    sohot Member

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    I notice that when setting up an account in WHM you now have the following options:

    Local Mail Exchanger
    Backup Mail Exchanger
    Remote Mail Exchanger

    I want to be able to offer my customers a backup email service if the primary mail server is down, but not sure exactly how this feature works.

    This is how I presume it works:

    I create a main cpanel account on one server which has the customers primary email accounts & web site etc.

    I create a secondary account on a 2nd server which is for email backup purposes.

    For the DNS zone (which is on DNSMadeEasy) I create two A records for the email: mail1.domain.com pointing to the IP address on the main account & mail2.domain.com pointing to the IP address on the secondary account.

    I also create 2 mx records: mail1.domain.com with a priority of say 10 & mail2.domain.com with a priority of say 30.

    So if the primary email is down for any reason the email should get sent to the secondary cpanel account.

    What I don't know is this:

    Where do the emails get stored on the secondary account? Do I need to setup any email accounts on the secondary account, or setup a default email account on the secondary account?

    Will emails automatically be forwarded to the primary account when the primary server is back online?

    Anything else I need to do for this to work properly?

    As I will be using DNS made easy for the DNS, can I safely delete the DNS zones for the account from the primary & secondary servers? (the Backup Mail Exchanger feature appears to ahve something to do with the DNS in cpanel, but not sure what as the zone looks exactly the same).
     
  2. sohot

    sohot Member

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    Dos'nt anybody know the answer to this?
     
  3. cPanelDon

    cPanelDon cPanel Quality Assurance Analyst
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    Depending on the configuration, the e-mails may only be stored in the secondary's server's mail queue until the primary server is restored to normal functionality.

    There is no need to create a duplicate account on the secondary server.

    Assuming e-mails are only held in the secondary server's mail queue, once the primary server is online it will eventually receive the missed e-mails within a nominal time frame, delayed only by the interval at which your Exim configuration reattempts delivery of queued messages, and the correct recipients should then receive the messages.

    If your secondary server is cPanel/WHM-based, you can use the following file to manage a list of which domains the system will serves as a secondary mail exchanger (MX) for:
    /etc/secondarymx

    I would not remove any DNS zones for active accounts; I would, however, retain them for reference and future comparison as this may prove useful in certain situations.

    We have additional documentation for this feature available at the following link:
    MXEntry < AllDocumentation/CpanelDocs < TWiki
     
  4. kat101

    kat101 Registered

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    Ok, but what I would like to know is, and no one seems to mention this, What if I wanted the emails which were sent to the secondary/backup mailserver to be forwarded to actual mailboxes instead of just sitting in the spool for later re-delivery to primary mailserver? The benefit is that users would be able to access their emails sooner. How would one achieve this via cPanel/WHM?

    Thanks
     
  5. shovi

    shovi Registered

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    @kat101 I don't know if you've figured this out yet given this is an older thread, but I looked into this same situation a while back. You'd need to be running a more sophisticated solution than just selecting the Backup Mail Server option to have users able to check their mail on the secondary server. The purpose of the Backup Mail setting is mostly so emails don't bounce back to the sender when the primary mail server is offline.

    You'd either have to set up a sync between the two servers to keep each user's mailbox account in sync so they can access either when the other is down, or look into a service (or third server) that worked like an Exchange server: it would check your mail based on whichever server is available, and you'd get it from there, not directly from the mail1 or mail2 servers.

    hope that helps.
     
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