When email from an unknown source is received and rejected, an email is sent by the NetSafa® SecurEmail® back to the sender, informing that the sender must be authorised to send email to the intended receipient. The email send contains instructions on how this is done; the sender simply has to reply to that email. Using a certain core DTM-technology, SecurEmail® learns the behaviour by determining the original sender's email address and subject and matching it to the sender's replied email address and subject. If there is a match, the email address is authorised and the email will be received, logged, and passed to SecurEmail® user. White List and Black List NetSafa® SecurEmail® allows its users the flexibility to define how they want to manage their email client. White List allows users to add in email addresses that they want to receive at all times, without going through the blocker. Eg. you always want to receive emails from john.smith@hisISP.com. You would add this email address into the White list. The same concept applies to the Black List; it just works in quite the opposite manner. This flexibility includes entering the email domain instead of addresses; eg. mail.com to the White or Black List. This gives companies greater flexibility to manage their NetSafa® SecurEmail®. History Log With History Log, you will never lose a single email. Here, you can view all emails sent to you, whether it is a SPAM email or not. If you decide that the email is not SPAM, you may 'Save to Contact', 'Move to Folder', 'Move to White List' etc. There is an option to 'Clear Log' when the History Log list is no longer relevant to you, or if it gets too long.