RE: [exim] Pobox and SPF

> > The problem is, sometimes exim allows bounced srs mails
> get thru and
> > sometimes don't:
>
> This is expected behaviour of SPF. It sometimes disallows
> genuine mail.

SPF never 'disallows' any email -- that is a choice of an admin
(or an email system configuration) perhaps BASED or
influenced by SPF records.

SPF is merely a system for declaring a domain or zone's authorized
(outbound) email servers.

Despite any hype or misinformation to the contrary, that is all that
SPF actually does.

It probably makes more sense to use SPF to affect a weighted
spam score (e.g., in SpamAssassin) than to block based simply
on an SPF calculation.

Many admins have misdefined their SPF records it appears or
have overlooked "additional" servers that SHOULD be authorized
in a complete specification.

It is also possible that servers not authorized by SPF but
performing no nefarious actions are NOT rewriting the SPF
(SRS) records when routing email through to other systems.