documenting the requirements for FreeBSD.org to send mail

[Warren Block]

On Thu, 17 Jan 2013, Eitan Adler wrote:

> I am working with clusteradm and postmaster to fix the freebsd-mail-bounces FAQ:
>
> Content and patch are pasted below.  The one concern is the manner
> that I described "Forward-confirmed reverse DNS" is too specific and
> knocks out correctly configured clients.
>
> In particular there does not have to be a 1-1 mapping, there just has
> to exist *a* mapping.  Can anyone suggest better wording for this
> specific case or general improvements for this question?
>
> ===== content =====
> The FreeBSD.org mail system implements some Postfix checks on incoming
> mail and rejects mail that is either from misconfigured relays or
> otherwise appears likely to be spam. Some of the specific requirements
> are:
>
> -- The IP address of the SMTP client must "reverse-resolve" to a hostname.
>
>    The IP address of the connecting host must have "reverse DNS" set
> up pointing to a domain which resolves back to the conneting IP
> address.

Typo (conneting).  But that sentence is confusing.  IP address to domain 
and back to IP address which must match the original IP address?

> -- The fully-qualified hostname given in the SMTP conversation (either
> HELO or EHLO) must resolve to the IP address of the client.
>
> Other advice to help your mail reach its destination include:
>
> -- Mail should be sent in plain text, and messages sent to mailing
> lists should generally be no more than 200KB in length.
>
> -- Avoid excessive cross posting. Choose one mailing list which seems
> most relevant and send it there.
>
> If you still have trouble with email infrastructure at FreeBSD.org
> send a note with the details to <postmaster at freebsd.org>;. Include a
> date/time interval so that logs may be reviewed ? and note that we
> only keep one week's worth of mail logs. (Be sure to specify the time
> zone or offset from UTC.)
>
> ===========
>
> patch:
>
> commit 9b12f8184246956a8adf4278757ad3d2747d49e7
> Author: Eitan Adler <lists at eitanadler.com>
> Date:   Mon Dec 3 00:21:40 2012 -0500
>
>    Update and clarify the freebsd-mail-bounces question (why mail to
>    freebsd.org bounces) to reflect reality.
>
>    Submitted by:       postmaster (dhw)
>    Approved by:        ??? (mentor)
>
> diff --git a/en_US.ISO8859-1/books/faq/book.xml
> b/en_US.ISO8859-1/books/faq/book.xml
> index 1b7ed76..55f4a8a 100644
> --- a/en_US.ISO8859-1/books/faq/book.xml
> +++ b/en_US.ISO8859-1/books/faq/book.xml
> @@ -8910,69 +8910,56 @@ hint.sio.7.irq="12"</programlisting>
>
>        <answer>
>          <para>The <hostid role="domainname">FreeBSD.org</hostid> mail
> -           system implements some of the stricter
> +           system implements some
>            <application>Postfix</application> checks on incoming mail
> -           and rejects mail that is either misconfigured or is
> -           potential spam.  Your mail might bounce for one of the
> -           following reasons:</para>
> +           and rejects mail that is either from misconfigured relays or
> +           otherwise appears likely to be spam.  Some of the
> +           specific requirements are: </para>
>
>          <itemizedlist>
>            <listitem>
> -             <para>The email is being sent from a known spam domain or
> -               IP block.</para>
> +             <para>The IP address of the SMTP client must
> +               "reverse-resolve" to a hostname.</para>
>
> -             <para>The &os; mail servers reject email from known spam
> -               sources.  If you have service through a company or
> -               domain who generates or relays spam, please switch to a
> -               service provider who does not.</para>
> +             <para>The IP address of the connecting host must have
> +               "reverse DNS" set up pointing to a domain which
> +               resolves back to the conneting IP address.</para>
>            </listitem>
>
>            <listitem>
> -             <para>The body of the email only contains HTML.</para>
> -
> -             <para>Mail should be sent in plain text only.  Please
> -               configure your mail user agent to send plain
> -               text.</para>
> +             <para>The fully-qualified hostname given in the
> +               SMTP conversation (either HELO or EHLO) must resolve
> +               to the IP address of the client.</para>
>            </listitem>
> +         </itemizedlist>
>
> -           <listitem>
> -             <para>The mailer at <hostid
> -                 role="domainname">FreeBSD.org</hostid> cannot resolve
> -               the IP address of the connecting host back to a
> -               symbolic name.</para>
> -
> -             <para>Working reverse DNS is a standard requirement for
> -               accepting mail from a host.  Set up reverse DNS for your
> -               mail server's IP address.  Many home services (DSL,
> -               cable, dialup, etc.) will not give you this option.  In
> -               this case, relay your email through your service
> -               provider's mail server.</para>
> -           </listitem>
> +         <para>Other advice to help your mail reach its destination
> +           include:</para>
>
> +         <itemizedlist>
>            <listitem>
> -             <para>The hostname given in the EHLO/HELO part of the SMTP
> -               exchange cannot be resolved to an IP address.</para>
> -
> -             <para>A fully qualified, resolvable host name is necessary
> -               in this part of the SMTP dialogue before mail will be
> -               accepted.  If you do not have a host name that is
> -               registered in the DNS, then you should use your service
> -               provider's mail server to relay your mail.</para>
> +             <para>Mail should be sent in plain text, and messages
> +               sent to mailing lists should generally be no more than
> +               200KB in length.</para>
>            </listitem>
>
>            <listitem>
> -             <para>Your message had a message ID ending with the string
> -               <quote>localhost</quote>.</para>
> -
> -             <para>Some mail user agents generate bad message IDs which
> -               will not be accepted.  You will need to persuade your mail
> -               user agent to generate a valid message ID or else
> -               configure your mail transfer agent to rewrite
> -               them.</para>
> +             <para>Avoid excessive cross posting.  Choose
> +               <emphasis>one</emphasis> mailing list which seems most
> +               relevant and send it there.</para>
>            </listitem>
>          </itemizedlist>
> -       </answer>
> -      </qandaentry>
> +
> +         <para>If you still have trouble with email infrastructure at
> +           <hostid role="domainname">FreeBSD.org</hostid> send a note
> +           with the details to
> +           <email>postmaster at freebsd.org</email>;.  Include a
> +           date/time interval so that logs may be reviewed —
> +           and note that we only keep one week's worth of mail logs.
> +           (Be sure to specify the time zone or offset from
> +           UTC.)</para>
> +    </answer>
> +  </qandaentry>
>
>       <qandaentry>
>        <question id="free-account">
>
>