Re: [exim] Alias to external server and SPF failure

On Sun, 2010-05-23 at 06:25 -0400, W B Hacker wrote:
> Stone me for an ignorant heathen, but what could possibly be wrong with ignoring
> BOTH SPF and SRS altogether?

Well... (takes a deep breath):

If a message arrives claiming to be from user@???, and
example.com has an SPF record of "-all", and you subsequently either
send the message through your filters, SpamAssassin, anti-virus and
perhaps even accept the message then you've completely wasted the
resources you have assigned to the message.

You won't actually *know* if SRS is in use - you may be able to deduce
with high accuracy from the envelope FROM format, but you won't know
absolutely. I suppose what I'm trying to say there is that you must
ignore SRS, because usage of it on a remote server has no relevance to
your server.

All that above is for operators of an MX, ie. those *receiving* mail.

"Ignoring" SPF and SRS on outgoing mail is left as an exercise for the
reader ;-)

Graeme