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295529Re: Reverse DNS unknown

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  • Dave Jones
    Sep 18, 2013
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      >On 9/16/2013 5:41 PM, Dave Jones wrote:
      >>
      >> Received: from mail02.corp.ena.net (unknown [96.4.3.90])
      >> by mr11.mail.ena.net (Postfix) with ESMTP id 57C091480688
      >> for <redacted@...>; Mon, 16 Sep 2013 16:04:46 -0500 (CDT)
      >>
      >> My forward DNS lookup for this host is an internal IP address that
      >> doesn't not match the public but it has been this way for years.

      > You need to do your tests as the postfix user, possibly also
      > chrooted. Turn off the chroot flag in master.cf for testing.

      I don't have anything chrooted (all n's in that column of the master.cf).
      The dig as the postfix user returns the same result.

      >> I
      >> didn't think the "unknown" above is dependent on FCRDNS.

      > but it is. For the conditions postfix will label a host as unknown,
      > please see
      > http://www.postfix.org/postconf.5.html#reject_unknown_client_hostname

      I am using reject_unknown_reverse_client_hostname in
      smtpd_recipient_restrictions but the server in question is covered by
      permit_mynetworks which is before it.

      > In the Received: header, the first name is the HELO name given, the
      > second is either the FCRDNS or "unknown". Postfix will also log a
      > warning explaining why the host is unknown.

      I see this in the maillog now that you mention it. It seems more
      informational than the cause of the "unknown" since I am using the
      "weaker" restriction above.

      warning: hostname mail02.corp.ena.net does not resolve to address 96.4.3.90

      Based on the reasons at
      http://www.postfix.org/postconf.5.html#reject_unknown_reverse_client_hostname,
      it shouldn't be "unknown" with the postfix user being able to resolve
      the PTR.

      > I don't know if the "unknown" by itself will trigger the
      > SpamAssassin RDNS_NONE rule, but that seems a little strict to me.

      On Mon, Sep 16, 2013 at 7:00 PM, Noel Jones <njones@...> wrote:
      > On 9/16/2013 5:41 PM, Dave Jones wrote:
      >>
      >> Received: from mail02.corp.ena.net (unknown [96.4.3.90])
      >> by mr11.mail.ena.net (Postfix) with ESMTP id 57C091480688
      >> for <redacted@...>; Mon, 16 Sep 2013 16:04:46 -0500 (CDT)
      >>
      >> My forward DNS lookup for this host is an internal IP address that
      >> doesn't not match the public but it has been this way for years.
      >
      > You need to do your tests as the postfix user, possibly also
      > chrooted. Turn off the chroot flag in master.cf for testing.
      >
      >
      >> I
      >> didn't think the "unknown" above is dependent on FCRDNS.
      >
      > but it is. For the conditions postfix will label a host as unknown,
      > please see
      > http://www.postfix.org/postconf.5.html#reject_unknown_client_hostname
      >
      > In the Received: header, the first name is the HELO name given, the
      > second is either the FCRDNS or "unknown". Postfix will also log a
      > warning explaining why the host is unknown.
      >
      > I don't know if the "unknown" by itself will trigger the
      > SpamAssassin RDNS_NONE rule, but that seems a little strict to me.
      >
      >
      > -- Noel Jones
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