Allow email protection rules to send notification to end user including header info such as sender address of blocked emails.
Rules to block emails and send notification to recipient user needs to also include the sender email address. a simple notification that an email was blocked and notify sender doesn't give the user enough info. they need an email address included.
As part of a roll out of DLP rules it would be good to send an email to the sender telling them that in the future an email may be blocked but today the email has been allowed. Preparing them for the later stage of DLP. At the moment there is no option to reply to a sender (I can send a notification to the recipient but not the sender).