Subject: [spfbis] Issue: forwarding and helo identities

From: Alessandro Vesely <[email-masked]>
Date: Fri, 10 Feb 2012 13:04:06 +0100

The advice given in the non-normative Section 9 is misleading.  On the
one hand, it provides overly cumbersome techniques based on macros
that are not universally considered safe.  On the other hand, it fails
to state the obvious point that a return-path is only needed if
someone is going to care about delivery failures.

When an email alias refers to an external domain, the forwarder must
change it.  This has to be normative, and update Section 3.9.1 of
[RFC5321] --not one of the best written sections of that paper.

Forwarding à la MAIL FROM:<> should be mentioned as the default,
easiest way to re-inject messages.  The implied interoperability is
that the owner of the target mailbox must be aware of a given
"forwarding recipe", and be able to modify or delete it.  The
variation MAIL FROM:<[email-masked]> is necessary when a
postmaster's action is needed for modifying/deleting a given recipe.
SRS should be mentioned as a general purpose variation for extended
forwarding needs.

The spec should say that an SPF record must be defined for every A or
AAAA record, irrespectively of whether its host label also appears in
some MX RRs.  We should encourage the use of _spf labels and redirect=
for designing sound and maintainable SPF compliance.