In order to ensure effective email delivery, we highly recommend that you setup email authentication in your DNS records. Email authentication is a way to tell receiving mail servers (Yahoo, AOL, etc) that Postmark (or anyone else specified) is allowed to send for your domain. It gets around spoofing, like when you receive a spam email from yourself. The other benefit today is that ISPs are now using email authentication to track your reputation. If authentication is used, you can build a positive (or negative, not recommended!) reputation on your domain to help improve delivery and trust over time. All around, it's a great thing to do.
While we already take care of SPF and DKIM on our side, it's important for you to create records for SenderID and DKIM on your own domain. Major ISPs such as Yahoo, Gmail, and Hotmail use this to verify the identity of your emails and track reputation.
To get started, login to your account and add a new Sender Signature. For each sending domain, we will provide the proper instructions for creating DKIM and SPF records in your DNS.