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reject_unknown_reverse_client_hostname RFC basis?

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  • Blake Hudson
    I was under the impression that hosts using SMTP were required to have a valid reverse DNS entry. The reject_unknown_reverse_client_hostname restriction would
    Message 1 of 3 , Dec 1, 2011
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      I was under the impression that hosts using SMTP were required to have a
      valid reverse DNS entry. The reject_unknown_reverse_client_hostname
      restriction would then enforce this requirement. However, I can't find a
      basis for this in RFC 821, 2821, or 5321. The closest I can find is
      helo/ehlo requirements. Is there, in fact, any requirement for sending
      hosts to have a valid rDNS entry?

      Thanks,
      --Blake
    • Michael Weissenbacher
      Hi Blake! ... To my best knowledge, no. It s just common practice. cheers, Michael
      Message 2 of 3 , Dec 1, 2011
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        Hi Blake!
        Am 2011-12-01 18:09, schrieb Blake Hudson:
        > I was under the impression that hosts using SMTP were required to have a
        > valid reverse DNS entry. The reject_unknown_reverse_client_hostname
        > restriction would then enforce this requirement. However, I can't find a
        > basis for this in RFC 821, 2821, or 5321. The closest I can find is
        > helo/ehlo requirements. Is there, in fact, any requirement for sending
        > hosts to have a valid rDNS entry?
        To my best knowledge, no. It's just common practice.

        cheers,
        Michael
      • Rod Dorman
        ... RFC 1912 Common DNS Errors 2.1 Inconsistent, Missing, or Bad Data Make sure your PTR and A records match. For every IP address, there should be a matching
        Message 3 of 3 , Dec 1, 2011
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          On Thursday, December 1, 2011, 12:09:42, Blake Hudson wrote:
          > I was under the impression that hosts using SMTP were required to have a
          > valid reverse DNS entry. The reject_unknown_reverse_client_hostname
          > restriction would then enforce this requirement. However, I can't find a
          > basis for this in RFC 821, 2821, or 5321. The closest I can find is
          > helo/ehlo requirements. Is there, in fact, any requirement for sending
          > hosts to have a valid rDNS entry?

          RFC 1912 Common DNS Errors
          2.1 Inconsistent, Missing, or Bad Data
          Make sure your PTR and A records match. For every IP address,
          there should be a matching PTR record in the in-addr.arpa domain.


          --
          rodd@... "The avalanche has already started, it is too
          Rod Dorman late for the pebbles to vote." - Ambassador Kosh
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