What is an email blacklist? | Email blacklist definition | EmailAcademy

An email blacklist is a third-party database containing the IP addresses or domains of people and organizations with poor email reputations. They're a significant component of the SPAM filters built into most email providers. These lists are often updated in real-time, as they help quickly determine whether an email is a SPAM (and should thus be filtered away from the user) or whether it is legitimate and can therefore be moved along into someone's inbox.

In this lesson, you will learn more:

What blacklists are.
Why ISPs and ESPs use blacklists.
How blacklists work.
The biggest blacklists you need to be aware of.

How Do Blacklists Work?

If the person you're sending an email to uses an email or Internet Service Provider that employs blacklists, it's essential to understand that ESP's will check the IP address of every incoming sender against the lists in question.

If your IP address happens to appear on that list, your email will be instantly flagged and will never get into the recipient's inbox. In some cases, they might even reject the email delivery, causing you a soft bounce visibility What is a soft bounce? Soft bounces are temporary email delivery errors that you might experience when sending an email marketing... Read more » .

The reason blacklists are in use

Overall, blacklists are important because email-driven cybercrime like phishing attempts are absolutely on the rise. Therefore, blacklists become an invaluable opportunity for providers to keep their users safe.

Likewise, people have less patience for marketing collateral these days and are looking for any opportunity to keep their inboxes less crowded. Blacklists go a long way towards helping them do precisely that.

Of course, all of this makes little difference if you're a non-spammer email marketer who suddenly finds themselves on an email domain blacklist accidentally.

An Overview of the Major Blacklists

Most Internet and email providers use at least one, or several, of the following email domain blacklists:

Composite Blocking List. This blacklists IP addresses that display objectively malicious behavior, like spambots.
Spamhaus Block List. This particular list focuses on known spam operations, along with their sources.
XBL Exploits Block list. This list is targeted at identifying IP addresses that have been "hijacked."
Barracuda. To get on this list, you typically need to have sent SPAM messages directly to a detector powered by the Barracuda Reputation System.

Why am I blacklisted?

If you find yourself on an email blacklist as a marketer, it's likely because you've been using the wrong approach to sending a large number of messages to people on your contact list.

There are many reasons why you might be blacklisted. Here you can see some of the most common ones that will likely eventually get you added to one of these lists:

Sending emails without the proper authorization visibility How to Test if SPF is Set up Correctly There's an old saying that email marketing professionals often use: "Test it and then re-test it. Read more » .
Sending emails to a large number of contacts who have not subscribed to receive emails from you.
Sending to large numbers of unverified email addresses.
Sending an extremely large number of outgoing messages.
Sending messages that have little to no personalization.
Using common SPAM words.