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

1. In your browser, log in to your Proton Mail account and go to Settings → Go to settings → Organization → Domain names → Actions column → Review button next to the domain you want to add a DKIM record for.

2. Select the DKIM tab. Here you will see the three host names and values that you will need to add to your domain’s DNS settings.

Important: If you manage DKIM in Valimail for your domain, you will need to add all the 3 CNAME DKIM keys on your domain's Configuration page in Valimail Enforce.

3. Once you have added these records, Proton Mail will handle the rest for you. Following current security best practices, we will generate a new 2048-bit key every six months and use it to sign your emails.

The CNAME records you add in Valimail Enforce must be an exact match with the ones shown in your setup wizard. Once we detect these records in your DNS, the DKIM tab will show a green tick icon. We will then notify you and start signing outgoing emails from your custom domain with DKIM, just like we do for other Proton Mail addresses.

You can also find the instructions on how to set up DKIM and SPF for ProtonMail, here.

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

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

You will find more detailed information on how to add a service for your domain in Valimail, here:

Note: 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.