Email Blacklisting: How Your Business Can Avoid It

What is an email blacklist?

The technical name for our subject is a Domain Name System-based Blackhole List, (DNSBL). It lists IP addresses or domain names associated with spam or suspicious content from low-trust senders. A DNSBL is a real-time database that can be updated at any time.

Email service providers, including Gmail, Outlook, and Yahoo, have live running blacklists and are always ready to add suspicious senders to them.

In December 2021, 45.37% of emails sent were spam (via Statista). The organizations that track spam complaints take it very seriously and work hard to keep the internet safe for everyone.

Each major email server, like Gmail, Outlook, and Yahoo, has its own running blacklist. That means if you get on Gmail's blacklist, you'll be prevented from sending emails to Gmail users. Some email providers share their blacklists with other email clients, creating a blanket effect. Some blacklists have more users than others and a few (such as Gmail and Outlook) have a significant share.

In other words, if you get on the blacklist of a popular email service provider, you'll likely lose access to many potential leads and returning customers. If you're on a smaller email blacklist, you might be able to ignore it.

Here are 8 email blacklists you definitely don't want to be on. The number next to each is a rating on a scale of 1 to 5, expressing how difficult it is to get off the list. One means very easy, and 5 means it's significantly challenging to get off the list.

• Composite Blocking List (CBL) (2)
• Spamhaus Block List (SBL) (3)
• XBL Exploits Block List (2)
• Spamcop (1, automatic)
• Passive Spam Block List (PSBL) (1)
• Invaluement (1)
• Barracuda (2)
• SenderScore (5)

These are the most prominent email blacklists out there, which serve major platforms like the ones mentioned above. If you find out you're on one of them, you want to have yourself removed from it promptly. We’ll cover how to remove your email from a blacklist later on.

How does an email blacklist affect your business

Blacklisting can have a negative effect on an email marketing campaign. It can cut off your access to new leads generated through surveys, activity on your website, and the lists of qualified leads offered by marketing service providers.

Perhaps even worse, blacklisting can deny you access to loyal, long-time customers who value and crave the content you offer. Should this happen, you could lose your most valued customers. Depending on the platform that blacklists you, it could cost you a significant percentage of your regular revenue.

How it works is that your deliverability rate will begin to drop. Depending on which lists you're on, deliverability rates can be reduced by different degrees. If the drop is small, you might not even notice. If it's major, with frequent delivery failures, you might be blocked by a big player like Google. If Google blacklists you, that is a significant problem, and you need to get off that list ASAP.

If you start getting many emails returned, that's a sign of a possible blacklisting. If it's happening a lot, that could mean you're on a major list, and it's time to investigate.

How to find out if your email is blacklisted

It can be tough to know for sure if you've been blacklisted. If you want to know the answer to "Is my email blacklisted?", sometimes Google will notify you. However, the email client doesn't always deliver a notification. If you notice a steep drop-off in responses and traffic, that might be the only sign you get.

You can check if Google has blacklisted you by making a Google account and viewing the Security Issues Report. There, you'll see a list of URLs that Google has been alerted to. If you find your site on the list, the first step is to clean your site of malware and let Google know you have fixed the problem.

If you learn Google isn't blocking you, you'll need to go down the list of databases to check email blacklist sites for your mail server IP address or domain name. The most common email blacklist checker sites are:

• GradeMyEmail Blacklist Checker
• MXToolbox's Blacklist Check
• Barracuda IP Blacklist Checker
• Whatismyip Email Blocklist Checker
• DNSBL Blocklist Check
• MultiRBL/DNSBLs Blacklist Lookup Tool
• Spamhaus IP Blocklist Checker
• IPVoid Blacklist Checker
• DNSChecker IP Blocklist Checker
• SpamCop

If you find you're on one of these lists, they'll have a protocol for removal. This usually consists of getting a report of the problems or suspected issues, clearing them up, notifying the database managers, and waiting. Most of the time, you can get removed easily, except in the case of SenderScore.

Getting your email removed from a blacklist database

Every platform and email blacklist has a protocol for getting removed from the list. Going back to our list of the big 8, you'll notice that it's pretty easy to get off most of them. SpamCop is odd because you can't do much other than wait. Sites are removed from SpamCop automatically after a period of time.

SenderScore, however, is quite challenging. A bit like changing your credit score, getting off the SenderScore email blacklist takes consistent effort.

If you get blacklisted by SenderScore, you'll need to address every problem that their report claims led to your low trust score. If this is the case, clean your site and network of malware, and consider cleaning your email list. When you have done these things, contact the web admin of SenderScore. They may not immediately take you off the list, and if they detect lingering problems with your site, you might stay on it.

To delist from SenderScore, your trust rating has to improve, which may take a while.

Tips to prevent your email from getting blacklisted

Avoiding email spam filters altogether can be tricky. If hackers are attacking your site or spoofing your email, you might get on a list to no fault of your own. This happens more often than we would like, but that's part of the reason it's usually easy to get off a list.

Here are a few things you can do to reduce the risk of your email being blacklisted.

• Create high-quality, engaging content
• Ensure your contact list is up to date
• Avoid spam words
• Refrain from sending mass emails via Internet service providers (ISPs)
• Get consent before sending emails
• Don't purchase email lists (some purchased email lists can contain spam traps)
• Remove email addresses with typos from your email list
• Ask contacts to verify their subscription with a double opt-in system

Avoiding email blacklists: Key takeaways

Blacklisted email compilations are unpleasant when we run into them, but they help keep the internet reasonably safe and usable. If you wind up on an email blacklist, don't take it personally.

Blacklisting can and does happen to many well-meaning people and quality businesses. Simply follow the steps outlined to remove yourself, and follow the tips mentioned earlier.

Mailchimp has many tools to keep your email lists in good order and help you stay off DNSBLs. We specialize in creating powerful marketing emails, and protecting you from being blacklisted is just part of the many ways we do that.