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SMTP Relay

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  • SMTP Relay


    Our email server is being hosted at our ISP but we want to send out some notification out from out SMTP relay from one of our servers, here the problem if we send out emails from out SMTP relay I am afraid some people has MX records lookup to see if MX records matches the domain name and if not it will drop it in a SPAM folder, any suggestion on how I can go about doing this? I already have two MX records recorded on the public domains, would adding a third one be an issue and will it resolve me SMTP relay issue? TIA

  • #2
    Re: SMTP Relay

    As long as it (a) has a lower priority = higher number than the ISP ones and (b) you accept the risk emails may be delivered to you if the ISP is down then there should be no issue adding the MX record. Whether it will resolve your spam problem remains to be seen

    Why can't you use your ISP as a smart host?
    Tom Jones
    MCT, MCSE (2000:Security & 2003), MCSA:Security & Messaging, MCDBA, MCDST, MCITP(EA, EMA, SA, EDA, ES, CS), MCTS, MCP, Sec+
    IT Trainer / Consultant
    Ossian Ltd

    ** Remember to give credit where credit is due and leave reputation points where appropriate **


    • #3
      Re: SMTP Relay

      The MX record of your domain has nothing to do with the delivery of your email to external recipients. Therefore setting another server in to the MX records is not going to help, and will actually cause more problems.

      As far as I am concerned, the value on MX records is meaningless. All MX records are equal. If you configure a server with a higher cost MX record then it will get email - mostly spam. Spammers actively target the higher cost MX record host because they believe (correctly in many cases unfortunately) that the higher cost host has lower levels of spam protection on it.

      The only thing that you can do DNS wise is ensure that the host you are using to send email has a valid PTR (aka reverse DNS record), which resolves to its external IP address correctly, and whatever the SMTP relay host is, it has that host name as its SMTP banner.

      That will not guarantee that you will not get flagged as spam - nothing can do that (otherwise spammers would be doing it). Ensuring the email doesn't look like spam will help more.

      Simon Butler
      Exchange MVP

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