Author: Martin Nicholas Date: To: exim users Subject: Re: [exim] SRS forward
It's obvious really, having thought a little:
The definitive test for SRS'ing is to make an SPF check for your outgoing IP
address against $sender_address_domain. This should be quite quick as the SPF
record will be cached by the DNS resolver. A 'fail' or 'softfail' means you
should use SRS to ensure delivery.