How to configure Mimecast to allow Mailing List emails

Mimecast specializes in email security for Microsoft Exchange and Microsoft Office 365.

Why Emails are Blocked

Mailing Lists are a special challenge for software that is trying to stop spam and malware.

Traditionally, mailing lists keep the original sender of the message in the From: header. However, the email is sent from the mailing list server, not from the original sender's ISP.

Some anti-spam settings will reject emails for this reason.

Mimecast Details

NOTE:
Mimecast is complicated. There are many places within Mimecast to set policies. Two ways to set up a policy allowing mailing list emails are described below.

Option 1

  • Navigate to the Gateway / Policies Tab.
  • The policy needs to be created in the “Permitted Senders” category, to allow receipt from your bulk mail provider.
  • Add Mail-List.com's IP addresses to the "Source IP Ranges" field.
    Mail-list.com IP addresses: http://www.mail-list.com/whitelist

See example below to create a new policy:

Option 2

See another example below to create a new policy. This is different way of accomplishing the same result as above.