I wrote a Salesforce email handler class in which I need to store the From address and later send emails to it. But I noticed that the from addresses were mangled for emails coming from my company.
Some investigation revealed that Salesforce was providing me the "Return-Path" header instead of the "From" header. Return-Path is where undeliverable messages are to be sent, not where human-generated replies are to be sent according to RFCs 3834 and 2821
These pieces of my headers look like this:
From: "Newman, Todd" <email@example.com> Return-Path: firstname.lastname@example.org
The prepended string on the email comes from Barracuda, it's a part of SPF email security.