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    Email Server Failover solution


    Hello,
    I have a question about a fail over solution of the Email server we host.

    We have a Microsoft Exchange server. We have two different T1 line for the email server. One T1's IP is 1.1.1.1 while another one is 2.2.2.2.

    Now we only use one T1 line and the public IP is 1.1.1.1. When people send an email to our company, the email goes to 1.1.1.1.

    We will use another T1 when the first T1 has problem. Assume the first T1 is down, the email people send will go to 2.2.2.2 instead of 1.1.1.1.

    Does anyone know how to do this? Or any companies like godaddy provide similar service? Thanks.
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    You would normally have two MX records created. Based on the priority used in the record (i.e., higher the number the lower the priority) that is how other mail servers will decide where to send the mail to your domain(s). If the server itself goes down, that's another matter; assuming it's your only mail server.
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    Thank you, seack79.

    Is this effective immediately? I mean, if the T1 (1.1.1.1) is down, then people send an Email to our server. Will this go immediately to 2.2.2.2? Or there is some delayed like a few hours or even 1 day?

    Thanks!
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    Wink


    It will be seamless, but for you to get any real benefit from this you'd want to have a 2nd mail server setup; pointing to the 2nd WAN IP. For instance, you might use:

    domain.com MX 10 mail1.domain.com
    domain.com MX 20 mail2.domain.com
    mail1.domain.com A 1.1.1.1
    mail2.domain.com A 2.2.2.2

    Where mail1 is your 1st mail server and mail2 is your 2nd mail server. I suppose in theory you could do the same thing with 1 server, but you will run into reverse DNS issues since I don't think the mail server can respond with more than one FQDN; probably shouldn't either.
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    Yes. we only have one email server.
    Last week when the T1 (1.1.1.1) is down, we switched to another T1 (2.2.2.2). We can still use our email server to send emails but not receiving emails.
    Adding a new Exchange server is less likely to happen right now.

    Can I manually update the MX record from


    domain.com MX 10 mail.domain.com
    mail.domain.com A 1.1.1.1

    to

    domain.com MX 10 mail.domain.com
    mail.domain.com A 2.2.2.2

    ?
    Will this also be seamless?
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    There are companies like zoneedit and others that offer backup mail server services.

    Like any DNS changes, manually editing the MX record won't be visible through the internet instantly, it may take hours to days for the change to propogate through the DNS server hierarchy.
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    Thank you, Doug.

    It seems manually updating the MX is not an option.

    I want to go back to what seack talked about. Can I do it this way:

    domain.com MX 10 mail1.domain.com
    domain.com MX 20 mail2.domain.com
    mail1.domain.com A 1.1.1.1
    mail2.domain.com A 2.2.2.2

    Then like seack said I will run into reverse DNS issue. Can I update the FQDN in mail server from 1.1.1.1 to 2.2.2.2?
    Once the T1 (1.1.1.1) is recovered, I change the FQDN back to 1.1.1.1.

    Will that be a workable solution? Will it work seamless once I update the FQDN?

    Thanks.
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    The way backup SMTP works the backup SMTP server will store incoming mail until the primary SMTP server becomes available again. The backup server needs to be configured properly to do this.

    I don't know if you can access the mail directly from the backup SMTP server or not since mail for the domain isn't being sent to a mailbox, it's in a holding tank (so to speak).

    fyi, this is from my reading, not from actually having set up or run a backup SMTP server.
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    That would not a viable solution. One thing to consider...email is obviously very important to your company. You may want to consider moving to a hosted solution. The cost is generally very reasonable.
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    Originally Posted by seack79
    That would not a viable solution. One thing to consider...email is obviously very important to your company. You may want to consider moving to a hosted solution. The cost is generally very reasonable.
    Thank you. I really appreciate for you guys' help. I did consider the hosting. But the cost seems a lot.

    I have another idea. How about pointing the mx record to a DDNS address?

    domain.com MX 10 MyCompanyMail.no-ip.com

    and MyCompanyMail.no-ip.com is a DDNS hosted by no-ip.com. It will update the IP address very quickly. If 1.1.1.1 is down, we can either manually or automatically switch it to 2.2.2.2.

    Like you ping MyCompanyMail.no-ip.com, it was resolved as 1.1.1.1 at first, after we update the DDNS, it will be 2.2.2.2

    And we did not change the MX record, so I think there should not be a delay? And that would be seamless?

    Do you think this is doable? Any suggestions? Thanks.
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    With all the manual work involved, you'd be just as well off to update the MX record on your own using the cPanel your DNS host offers. To really do what you're wanting, I think you'd need to WAN circuits, and multiple mail servers (or atleast two virtual servers on the same physical box). If your WAN link isn't that unstable, which most have a 99% uptime, you probably don't need to be too worried about it unless someone up top is wanting you to look into this?

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