Connect Application: Importing Permitted Senders

Document created by user.oxriBaJeN4 Employee on Oct 22, 2015Last modified by user.Yo2IBgvWqr on Dec 5, 2017
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Applies To...


  • New clients connecting with Mimecast using the Connect Application. If you are not using the Connect Application, click here.




To protect you from spam, we apply strict screening to all inbound emails from unknown external senders. When you first connect with us, we do not know who you regularly communicate with. As we treat all external senders as unknown, your inbound email processing can be slowed down. 


To ensure email from your trusted senders bypasses our spam scanning, you can let us know in advance who you regularly communicate with. To help you, we've provided an application that you can download and run over a period of days. It gathers details of your known external email addresses, outputting them to a CSV file. When you're ready, you can import the CSV file to add these users to your permitted sender list.


This involves the following tasks:

  1. Download and run our Contacts Export Wizard app. The app produces a list of known addresses in a CSV file.
  2. Add any additional permitted senders to the CSV file manually, if required.
  3. Import the CSV file in the Connect Application. The addresses are added as permitted senders.


What You'll Need


  • .NET Framework version 4 installed on a Windows PC or server.
  • The Contacts Export Wizard application (see below).
  • An account with Application Impersonation.
  • For an On-Premises Exchange installation, a publicly published EWS endpoint (Exchange 2007 SP1 and later).




Import Permitted SendersTo import permitted senders:

  1. Navigate to Gateway | Import Permitted Senders.
    The current number of Permitted Senders is displayed.
  2. Click the Start button.
  3. Click the Download button. The Mimecast Contacts Export file is downloaded to your browser's download location.
  4. Run the application and follow the instructions. It runs in the background gathering details of who you communicate with.
  5. When you're ready, stop the application. The .CSV file is saved to your browser's download location.
  6. If required, open the CSV file and add more email addresses and domains manually.
    To manually add email addresses to the CSV file, use the format "<internal user address>, <external address>, PERMIT". For example: ", PERMIT"
  7. To import the CSV file, either: 
    • Click the Select CSV File button and select your saved CSV file from the browser that opens.
    • Drag the saved CSV file directly into the file field.
  8. The file is automatically uploaded and imported if validation is successful.
  9. A summary displays the number of permitted senders successfully added. Any errors will be listed under Import Error Report on the summary page. Fix the errors in the file, and click the Import More Permitted Senders to resubmit the senders.
    The maximum rows per upload is 50,000. If you have more senders, perform multiple uploads.


See Also...