Recipient address verification ensures that the FortiMail unit rejects email with invalid recipients and does not scan or send them to the protected email server. This verification can reduce the load on the FortiMail unit when a spammer tries to send messages to every possible recipient name on the email server.

If you want to use recipient address verification, you need to verify email recipient addresses by using either the email server or an LDAP server.

Usually you can use the email server to perform address verification. This works with most email servers that provide a User unknown response to invalid addresses.

For instructions on configuring recipient address verification, see “Configuring protected domains”.