Sending to Comcast? Be aware!

A Comcast friend has shared, on another forum, some information regarding best practices when sending emails to comcast.net email addresses. I'm sharing that information here with permission.

1. DMARC policy change coming: Comcast's "comcast.net" domain (where subscriber mailboxes live) will be moving to a "p=reject" DMARC policy in the near future. Their subdomain policy (sp=) is already set to reject. The impact? This will restrict use of the comcast.net domain as a sender address when not using Comcast's infrastructure. Meaning, don't send your email newsletter with a comcast.net address in the from field.
2. Email Authentication: Please ensure that all of your email messages to comcast.net are authenticated. Given that with Microsoft's recent announcement of updated bulk sender requirements, we're quickly reaching a point where all of the largest mailbox providers are either suggesting or requiring that email senders should be properly utilizing email authentication (i.e. SPF and DKIM) when sending messages. No surprise there to hear that Comcast wants this, too.
3. Utilize TLS over SMTP: Ensure that your mail server utilizes TLS encryption (v1.2 or v1.3) when delivering messages to Comcast recipients. (Like with many mailbox providers, they do not support older versions of TLS, due to inherent security issues.) If you're using a modern email sending platform, those in charge of managing the technical bits for that platform behind the scenes should already be on top of this one. But it's good to call it out, just in case.

Want to learn more about requirements and best practices for sending email to Comcast mailboxes? Find their Postmaster page here.