[Mimedefang] Received headers in general

[David F. Skoll]

On Wed, 23 May 2012 00:26:25 -0700 (PDT)
kd6lvw at yahoo.com wrote:

> Not at all.  Malformed messages may always be rejected.

You can reject messages containing a prime number of "e's" if you like,
but that doesn't make it a good idea nor does it follow the spirit
of the RFC.

> This says nothing which forbids rejecting messages for
> failing to meet SMTP syntax when transported via SMTP (or when they
> claim such by stating "with SMTP" in the header data).

I disagree.  You are projecting your interpretation on the RFC authors.
They say you MUST NOT reject a message for a bad trace header.  It further
says that one reason for bad trace headers is non-SMTP systems.  It does
not say it's OK to reject because of a bad trace header from an SMTP system.
You're reading text that isn't there.

> If you're saying that we can't check a required syntax when it MUST
> be generated,

If you're writing an RFC-compliance checker, you SHOULD be as strict
as you can.  If you're attempting to interoperate widely, such
strictness is an impediment to interoperability.  Remember, the goal
of Internet RFCs is to allow people to communicate, not for some
people to show how much smarter they are than others.

Regards,

David.