Mimecast

To create a DNS record, follow these steps:

1. Update the SPF records for your domains with the information displayed in the application under SPF Record, as shown below:

v=spf1 include:_netblocks.mimecast.com ~all

1. Log in to your Domain Registrar
2. Update/replace each domain’s SPF record to specify Mimecast as the authorized outbound service
3. If all email for your domains will be routed via Mimecast, remove all previous SPF records
4. Other outbound sources for your domain might require a combined SPF record; In this instance, ensure you include the Mimecast “xx_netblocks.mimecast.com” entry before creating a mail flow connector; To determine what “xx” is, refer to step 1 above
5. Optionally test your SPF record:
6. Navigate to Platform/Set Up Your Outbound Email in the Connect Application
7. Select your domain from the Record to Validate dropdown menu
8. Click on the Validate button; One of the following messages will display:

• A green tick confirms the SPF record is valid
• A red exclamation point confirms the SPF record is invalid
• Click on the More or Less links to view further information about the SPF record and toggle the display

Note: If you already have an SPF record, merely add the following before the ~all mechanism:

include:_netblocks.mimecast.com

Mimecast utilizes an include mechanism during the set-up process. For example, the following scenario is the most common (global) and would pass SPF:

v=spf1 include:_netblocks.mimecast.com ~all

If you send email from IP 1.2.3.4 for the domain “yourcompany.com” and that domain’s SPF record includes _netblocks.mimecast.com and the IP address passes the SPF record, this mechanism will pass.

Moreover, Mimecast does not allow for a custom Return-Path address to be used, which is a designated email address where bounced messages are sent. By customizing a Return-Path, the ability to present customer emails in a more professional manner (i.e., removes the default third-party “on behalf of” designation) is achieved.

How to Set Up/Modify DKIM for Mimecast

To do this, create an Outbound Signing Definition. Once this definition is produced, it will inform you what needs to be added to your DNS record. For more information on implementing DKIM for Mimecast, click here and follow the “Set Up DKIM for Mimecast” path.

As a user of this outbound email provider, Mimecast customers are afforded DKIM signing because it supports this mechanism. By utilizing its self-service portal, you can manually set up DKIM at your convenience. Overall, Mimecast provides DKIM signing and self-service set up, resulting in a streamlined process.