Problem

Customers are concerned about this technique which allows senders to bypass mime spoofing defenses.

More info on how to here: https://web.archive.org/web/20191202140703/https://www.mailsploit.com/index

Resolution

Create address rewriting rule as shown in the pictures below:

In this case every attempt with any encoded address will be rewritten to what you have chosen and alternatively you can create filter policy (If message is sent from Bobby@Axway.com in the From Header) to quarantine the message and send notification to admin for review.