How to Optimize Email Deliverability for Your Comcast Users

How’s your email deliverability for subscribers who use Comcast as their Internet service provider (ISP)? Comcast has a reputation for being rather quick to block senders, so you may find it challenging. Here, we focus on deliverability issues specific to Comcast based on some of the latest information revealed at the 2015 Email Evolution Conference (EEC).

The final session at this year’s EEC featured four representatives of the largest ISPs – including Matthew Moleski from Comcast – who answered questions from email marketers on deliverability.

How Can You Get Your Emails Through the Comcast Spam Filters?

According to Moleski, Comcast filters out about 95% of the emails that arrive at the company’s proverbial front door because they’re spam. So even if your company is part of the 5% that is permission-based and following best practices, you still need to be vigilant.

Comcast has become more transparent when it comes to how they filter spam. In fact, check out this link that lists the nine things you need to know to get through Comcast’s spam filters. At the conference, Moleski highlighted the following four items that marketers need to pay attention to:

  • Get your Internet Protocol (IP) address properly authenticated. Essentially, email authentication verifies that the domain used in the from address is really under the control of the sender, which protects email users from spammers and phishing scams. That’s why it’s also important to keep your IP reputation clean – not associated with organizations that send spam, spyware, or other deceptive emails.
  • Stay off Domain Name System Blacklists (DNSBLs) and keep your distribution lists clean. ReturnPath and Spamhaus Zen are two examples of the DNSBLs that Comcast uses. If you’re on one of the lists, Comcast won’t be the only ISP blocking your emails. Plus, be sure to treat all non-delivery notifications (NDNs) as an unsubscribe request since a large number of undeliverable emails will cause the sending IP to be blocked.
  • Design messages that are intriguing. This is an important way to engage users. And, as we covered in a recent overview article on email deliverability, engagement is key to email deliverability. You’ll also find the factors that determine a sender’s deliverability in that article.


What About Migrations & Spam Traps at Comcast?

Comcast representatives will work with professional email marketers on large migrations. Moleski indicated that they are fully aware that email marketers are constantly changing vendors, and Comcast will readily assist you with any IP migrations.

Email marketers at the conference expressed their concern about what happens when a subscriber disconnects his or her email service. Do ISPs convert them into spam traps? Moleski indicated that Comcast doesn’t do that; rather, they inactivate the email addresses. Most Comcast spam traps are brand new, never used email addresses. And they are obvious spam traps – typically made up of random characters.

What Should You Do If You’re Having Comcast Deliverability Problems?

Moleski said that his team would assist marketers having difficulty getting through Comcast spam filters. The underlying caveat, however, is that your organization must be using professional, permission-based email-marketing practices.

If your email campaigns get blocked by Comcast, you can submit an online request to be removed from the spam list at the following link:

So what can email marketers do to help optimize Comcast deliverability? Moleski suggested that you work with your metrics to better understand your email campaign trends. In this way, you’ll see how subscribers are engaging with your emails so you can send better messages. In addition, it also doesn’t hurt to build relationships with your receiving ISPs.

If your company is looking for ways to optimize your email deliverability, FulcrumTech can help. Email us or give us a call at 215-489-9336 and get started today.

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