Advanced and Federated Accounts - Emails To Unknown Internal Users

This guide describes how the Emails To Unknown Internal Users option works, and how you can select the option. It is intended for Administrators.

If you are using the Advanced Account Administration Console, you can choose how emails to an unknown internal user are handled. An option called Unknown Address Type is available in the Mimecast Administration Console, allowing you to select whether messages to an unknown internal user are temporarily deferred, or rejected.

This option is only available on a Master account and you need to have Master Administrator permissions to change the setting.

You can select how emails to an unknown internal user are handled, by using the following steps:

1. Log in to the Administration Console.
2. Navigate to Account | Account Settings.
3. In the Unknown Address Type setting, select one of the following:

• • 451 Deferral: This is the default setting. If selected, emails to an unknown internal user are temporarily deferred with a 451 code. The sender can retry multiple times, allowing the Administrator an opportunity to synchronize the directory or create the user manually.
  • 550 Rejection: If selected, and an email is sent to an unknown internal user, the sender will receive an Invalid Recipient code resulting in a Non-Delivery Report (NDR). The failed delivery information is then logged in Monitoring | Rejections in the Master account.

4. Click on the Save button.

See Also..

• Managing Internal Domains