documenting the requirements for FreeBSD.org to send mail
Eitan Adler
lists at eitanadler.com
Thu Jan 17 16:12:44 UTC 2013
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.
-- 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">
--
Eitan Adler
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