This article covers the SPF and DKIM authentication processes for Postmark and how they are managed in Valimail Enforce. While only one of the two authentication methods is required for an email to pass DMARC, our recommendation is to configure both whenever possible.


Configuring DKIM authentication for your Postmark emails

1. Navigate to your Sender Signatures tab in your Postmark account.

2. Under the domain you are adding DKIM authentication for, click DNS Settings or Add a DKIM DNS record.

3. A DKIM record will be shown that needs to be added to your DNS as a TXT record.

4. The Postmark TXT DKIM key record needs to be published in Valimail Enforce.

5. Once the record is added Valimail Enforce, DKIM will show as verified in your Postmark account. You can use the Verify button to initiate a manual verification check if you do not see the record automatically become verified.

6. After the DKIM record is verified, we will begin signing emails sent through Postmark using this domain with DKIM.

You can find the instruction on how to set up DKIM in Postmark here.

Add a Postmark DKIM key in Enforce

1. Go to your domain's Configuration page in Valimail Enforce and publish the newly created DKIM key.

    a. Scroll down and add the DKIM key in your configuration, by clicking on Add a DKIM key

    b. Enter the selector name, the DKIM TXT value (the actual value is the entire string after the p= tag), associate the key with Postmark and then click Add.

You can find more detailed information on how to add a DKIM key in Valimail Enforce here.

Configuring SPF authentication for your Postmark emails

Once you establish that Postmark is an authorized sender for your domain, you will need to add the service in your Enabled Senders list in Enforce.

1. Please go to your domain's Configuration page in Enforce.

2. Click on the + sign from the Enabled Senders section:

3. Choose Postmark from the list of configurable senders and then click Enable:

We encourage you to use the comment section for any useful information about your sending service, such as the name of the service owner, change request ticket numbers, etc.

Enable SPF alignment in Postmark for your domain

You may notice that Postmark emails are not authenticated via SPF, even after you have added Postmark to your domain's configuration. This is likely caused by Postmark not sending SPF aligned-mail and can be corrected by configuring a CNAME record.

More details on how to achieve that are found in the article here.

As always, if you have any questions, please don't hesitate to submit a ticket.