I have got a question regarding how one can protect himself from fake e-mails that are forged by putting in a fake message header while keeping normal envelope header? The issue is that what is displayed in an e-mail system is the message header that is not really verified (see an example below):
data 354 End data with <CR><LF>.<CR><LF> From: Display this fake address <email@example.com> To: Recipient <firstname.lastname@example.org>
I can literally put anything in the From and To headers and this is what is going to be displayed to the recipient. This is because the verification steps are done for the "mail_from:" and "rcpt_to:" which might be genuine but the message itself is faked in the message headers.
Are there any steps one can take to verify message headers to check if a message is genuine?