With Constant Contact there are a few options to authenticate your email. However, there is only one way to authenticate your emails and be DMARC compliant.
SPF
In order to authorize Constant Contact to send emails on your behalf you will have to include them in your SPF record. The “include” mechanism used by them is:
include:spf.constantcontact.com
DKIM
In order to implement DKIM you will have to email Constant Contact and let them know that you would like to self-authenticate your custom domain. They will email you back with the necessary information about the records that need to be published in your DNS.
For more information about authenticating your domain with Constant Contact please click on the button below.
Create a free OnDMARC account to test your configuration.