2.4.3 Maximum number of email addresses

MetaDefender Email Security is licensed based on the maximum number of recipient email addresses.

Recipient email addresses are counted by MetaDefender Email Security using the following method:

  1. If there is an inbound security rule(s) defining the corporate domain(s) then only recipient email addresses belonging to that domain(s) are counted

  2. Else all recipient email addresses are counted

Sender email addresses are not counted for license.

A recipient email address is enrolled for one email address license once it is received by MetaDefender Email Security as a RCPT TO SMTP header.

The email address holds its share of the licenses for 72 hours after its last activity noticed by MetaDefender Email Security (the last occurence of the email address as a RCPT TO SMTP header).

Once the 72 hours reservation time elapses after the last activity, the email address license is released and can be reused for any (other) email address.

License limit reached

When maximum number of licensed email addresses is reached then the email is simply blocked by MetaDefender Email Security on its incoming SMTP interface. As a consequence these blocked emails won't enter the processing pipelines of MetaDefender Email Security.

Multiple recipients

If an emails has multiple recipients of which some are under the limit (already counted for a license) and some are over the limit then

  1. The email is processed for the recipients which are already counted for a license and

  2. The email is refused for the recipients which would exceed the license number limitation.

Email history and logs

The Web Management Console page Dashboard > Email history prints no messages for emails that are over the license limit as these emails have not entered MetaDefender Email Security.

The MetaDefender Email Security logs print Recipient license count exceeded warning message for entries blocked by exceeding maximum email address number limit.