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  • Exchange as Backup mail system?

    I'm wondering if exchange can be used for the following situation:

    I provide IT support to many business (domains) who run there own exchange systems on site.

    There server goes down so dns points mail to fail over service at my office. There mail is accepted by my server and stored.

    Once there server is backup it contacts my server asking for the stored mail to be resent.

    ................................................

    So i want to use exchange 2003 or 2007 to do this. I know i would need to add every clients domain to my server so it execpts mail.
    ..................................................

    How would exchange be configured?
    Would I have to configure each mail box for every user for all cients?

  • #2
    Re: Exchange as Backup mail system?

    Exchange is a poor choice for this.
    How would you get the email from your server to their server?

    How are you going to manage the DNS? If you think that putting your server in the MX records will work, then you need to think again, because your server will receive email.

    The way that I do it is to use a dynamic DNS service.
    http://www.sembee.co.uk/archive/2007/02/02/38.aspx

    In the event of a failure I can then redirect the email somewhere else to be stored.
    However, I haven't had to use that system to direct to alternative servers for over 12 months. Most issues have been down to ISP failures and I will usually use a dial up account to get email to flow.

    Also don't forget that as long as the server is available within 48 hours, no email will be lost. If you are going to be down for more than 48 hours then I work on the principle that you have bigger things to worry about.

    Don't try and setup something that protects you against something that might happen once a year, but causes ongoing problems.

    Simon.
    --
    Simon Butler
    Exchange MVP

    Blog: http://blog.sembee.co.uk/
    More Exchange Content: http://exchange.sembee.info/
    Exchange Resources List: http://exbpa.com/
    In the UK? Hire me: http://www.sembee.co.uk/

    Sembee is a registered trademark, used here with permission.

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    • #3
      Re: Exchange as Backup mail system?

      Hi Simon

      Firstly I would like to thank you for the swift update.

      I wasn't aware of the 48 hrs time frame so this new found knowledge is enough for me to can the whole idea.

      Happy days.....

      Comment


      • #4
        Re: Exchange as Backup mail system?

        I'm not sure how appropriate this will be to your situation, but... here's what I do for every company I've worked with.

        We setup the MX records in DNS to point to the Exchange server first, and an offsite server second. Each customer gets a single mailbox on the offsite server, which receieves all mail sent to that domain if the Exchange server goes down. When Exchange comes back up again, it is configured to connect to the external mailbox using POP3 and download the messages.
        Gareth Howells

        BSc (Hons), MBCS, MCP, MCDST, ICCE

        Any advice is given in good faith and without warranty.

        Please give reputation points if somebody has helped you.

        "For by now I could have stretched out my hand and struck you and your people with a plague that would have wiped you off the Earth." (Exodus 9:15) - I could kill you with my thumb.

        "Everything that lives and moves will be food for you." (Genesis 9:3) - For every animal you don't eat, I'm going to eat three.

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        • #5
          Re: Exchange as Backup mail system?

          Originally posted by gforceindustries View Post
          I'm not sure how appropriate this will be to your situation, but... here's what I do for every company I've worked with.

          We setup the MX records in DNS to point to the Exchange server first, and an offsite server second. Each customer gets a single mailbox on the offsite server, which receieves all mail sent to that domain if the Exchange server goes down. When Exchange comes back up again, it is configured to connect to the external mailbox using POP3 and download the messages.
          If you read the blog posting I have linked to above you will see why I consider the backup MX record method to be a bad idea.
          In short the second MX record becomes a spam trap, it will receive valid email messages, so whatever transfer solution you have needs to run always and you lose the ability to filter email based on recipient. For the odd system or internet down failure I consider that too much loss for very little gain.

          Simon.
          --
          Simon Butler
          Exchange MVP

          Blog: http://blog.sembee.co.uk/
          More Exchange Content: http://exchange.sembee.info/
          Exchange Resources List: http://exbpa.com/
          In the UK? Hire me: http://www.sembee.co.uk/

          Sembee is a registered trademark, used here with permission.

          Comment


          • #6
            Re: Exchange as Backup mail system?

            Originally posted by Sembee View Post
            you lose the ability to filter email based on recipient
            When Exchange downloads the mail over POP3, it will attempt to determine the correct recipient and process any applicable rules as if the message had been delivered directly to the Exchange server. While your approach is preferable, it requires someone to intervene in the event of an outage.
            Last edited by gforceindustries; 20th October 2008, 13:38.
            Gareth Howells

            BSc (Hons), MBCS, MCP, MCDST, ICCE

            Any advice is given in good faith and without warranty.

            Please give reputation points if somebody has helped you.

            "For by now I could have stretched out my hand and struck you and your people with a plague that would have wiped you off the Earth." (Exodus 9:15) - I could kill you with my thumb.

            "Everything that lives and moves will be food for you." (Genesis 9:3) - For every animal you don't eat, I'm going to eat three.

            Comment


            • #7
              Re: Exchange as Backup mail system?

              Originally posted by gforceindustries View Post
              When Exchange downloads the mail over POP3, it will attempt to determine the correct recipient and process any applicable rules as if the message had been delivered directly to the Exchange server. While your approach is preferable, it requires someone to intervene in the event of an outage.

              And?
              The message has already been delivered. The bandwidth is being wasted. Recipient filtering can drop 1000s of messages at the point of delivery and is the most efficient way of working.
              By its very nature a backup MX record will get more spam than the primary connection.

              POP3 connectors also have a problem with messages that were sent under BCC. If you are pushing the messages through the SMTP engine then the messages will be lost because there is no routing information for SMTP to use.

              I agree that my approach requires manual intervention, but when you consider that most email servers will continue to try and deliver email for up to 48 hours, a manual switch which takes 30 seconds is a lot more preferable than the loss of functionality.
              If you are down for an hour or so then the change is not worth it. If you are going to be down longer than that then someone else is involved and there should be a procedure for dealing with the downtime.
              If you are having to use the backup system so frequently that you want it to be automatic then you need to look at why you have periods of downtime.

              What I don't like is crippling the functionality of Exchange or email in general (and using a POP3 based solution is a cripple) to protect for something that should not happen very often. That is like taking a detour to use an underpass a mile away just in case you get hit by a car when crossing the road!

              Simon
              --
              Simon Butler
              Exchange MVP

              Blog: http://blog.sembee.co.uk/
              More Exchange Content: http://exchange.sembee.info/
              Exchange Resources List: http://exbpa.com/
              In the UK? Hire me: http://www.sembee.co.uk/

              Sembee is a registered trademark, used here with permission.

              Comment

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