How to reject/detect emails claiming to be from my own domain?

[Mark Sapiro]

On 12/29/2016 09:50 AM, Philip Parsons wrote:
> I am trying to get one that does the envelope-from header so at the MTA
> side of things.  I am hoping someone has done this with sendmail as
> changing the MTA is not possible at the moment.  The rule set from Thom
> van der Boon works great on the From header.


But, with sendmail and other compliant MTAs, the envelope sender will be
put in a Return-Path: header, so if you alter the From: rules that work
to look at Return-Path: instead, that should deal with envelope senders.

-- 
Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan