451 4.1.8 Possibly forged hostname

Discussion in 'Installation/Configuration' started by wpwood3, Nov 30, 2007.

  1. wpwood3

    wpwood3 New Member

    There is one ISP that is rejecting mail from my mail server with the following error:

    451 4.1.8 Possibly forged hostname for
    My domain is mercedesshop.com.

    Is there a problem with my mail server or is the issue with that ISP?

    This is the definition I found for error 451 4.1.8:
    "This means that it was able to resolve the IP address, but it doesn't resolve to a hostname that matches both forward and reverse lookups."

    Please note that all of my incoming mail is routed through a proxy mail server to filter spam and viruses. I would not think that would make any difference for SMTP.
  2. wpwood3

    wpwood3 New Member

    Since my servername is mbshop2.mercedesshop.com
    Would it help if I added an A record for mbshop2?

    I am not using mbshop2 as a hostname for any of my webs.
  3. wpwood3

    wpwood3 New Member

    I'm going to try adding the A record for mbshop2 and see if it fixes the problem.
  4. wpwood3

    wpwood3 New Member


    Adding an A record for mbshop2 seems to have fixed the problem with the one ISP that was refusing email from my server.

    Now on to the next problem...
    I have another customer who is not getting emails from us. This one has a US Army email address. Whenever my mail server sends to him the connection times out. This one may be tougher to solve because there's no error code.
  5. falko

    falko Super Moderator ISPConfig Developer

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