About Denylists

Denylists (other providers may refer to it as "blacklist") are intended to help identify and block domains or IP addresses that distribute harmful content. These lists are often compiled by inbox service providers (ISPs) and denylist operators to help protect people, but sometimes domains and IPs get denylisted when they shouldn't be. To help keep Mailchimp’s IPs off denylists and ensure our service is reliable, we enforce certain rules when you create and send emails.

In this article, you'll learn about denylists and how they affect the work you do in Mailchimp.

Definitions

First, let's define a few important terms.

• Domain
  The name of a website. For example, mailchimp.com.
• IP address
  A unique string of numbers that identifies a particular server. For example, Mailchimp has thousands of IP addresses that identify our servers to ISPs.
• Denylist
  A list of blocked email addresses, domains, or IP addresses. For example, web browsers will prevent users from accessing websites that are denylisted, and email providers may block mail that comes from denylisted domains. Many denylists are public, but most large ISPs maintain private denylists.

How do you get denylisted?

There are lots of ways you can end up on a denylist, but it often has to do with email. If you receive a high volume of complaints from your recipients, you may end up on a denylist. Or, your emails may be marked as spam, or blocked just for being marketing content.

Denylists are intended to protect against harmful or malicious content, but they're not perfect. If you think you may be on a denylist, don't worry, it's usually temporary. Usually, you'll be removed after some time has passed and there aren't any lasting effects.

Can Mailchimp get denylisted?

Anyone can get denylisted, but we have extensive policies in place to keep Mailchimp off denylists. We prohibit certain content that could be considered harmful and actively monitor reputable denylists like Spamhaus, Invaluement, Barracuda, Frontbridge, and SURBL. If a Mailchimp server does end up on a denylist, we investigate immediately and get it removed as soon as possible.

You may also hear the term "greylist." These lists identify bulk email providers so private domains can block them if they don't want to receive email marketing at all. Because Mailchimp has a bulk email service, we're sometimes on greylists. It's a good idea to have your subscribed contacts allowlist Mailchimp's IPs to keep your emails from bouncing.

What does this mean for me?

Sometimes, you’ll get denylisted despite your best efforts. Still, it’s important that you take precautions to avoiding being denylisted, especially when you’re using Mailchimp. This helps ensure your marketing campaigns reach your contacts, and it helps protect Mailchimp from being denylisted, as well. Here are some general guidelines.

• Respect contact permission levels.
• Don’t distribute content that violates our Terms of Use and Acceptable Use Policy.
• Don’t use denylisted affiliate links in your emails.