Your complete guide to email blocklist removal

Your email marketing efforts have been going great. You’ve been sending out creative campaigns, ramping up engagement, and even seeing more conversions. Then, BAM! Out of nowhere, you’ve landed on an email blocklist. 😱

An email blocklist is a collection of email server IPs associated with spam—not where any business wants to find itself. But it can happen to the best of us! 

Whether you’re having deliverability issues due to being blocklisted or want to know how you can check whether you are—our guide has you covered. You’ll learn about the different types of email blocklists, the signs to look for, why IPs get blocklisted, and how you can get your IP removed. 

Email blocklists are lists of servers, domains and IP addresses that have been flagged for sending spam. 

There are many different blocklists available, each of which has varying impacts on email delivery for those that land on them. Some of the more reputable and well-known blocklists are Spamhaus, Barracuda and SpamCop.

Different IP blocklists are used by spam filters, Internet Service Providers (ISPs) and mailbox administrators to detect spam for their users. 

There are two types of email blocklists: 

  • Internal email domain blocklists are usually owned by mailbox providers, for example, Google. A company mailbox administrator could also set up their own internal blocklist. In this case, the owner of a blocklisted IP would contact the mailbox provider or administrator, as they are the owner of the blocklist. 
  • External email domain blocklists, which we will focus on in this article, are owned and managed by a third party. Mailbox providers can use these blocklists to filter out incoming spam. If your IP has made its way to an external blocklist, you would need to contact the third party. 

One of the first inklings that your email has been blocklisted is lower open rates and a sudden increase in bounces. 

If you’re using an Email Service Provider (ESP) you’ll need to take this up with them. If not, the bounce message you receive will relay some information about the reason your email was bounced. 

For example: “Reason: Sender IP (000.00.00.000) is blocklisted at zen.spamhaus.org.”

Even if your bounce rate hasn’t increased, or you’re not receiving bounce messages like the one above, this doesn’t mean you’re out of the woods! Some smaller domain blocklists have a low impact on email deliverability, and therefore may not affect your sendings. 

Does this mean you can just pretend everything is fine and dandy? That wouldn’t be a good idea, because being on these blocklists might cause future issues. It’s better to be proactive to ensure you maintain the healthiest sending behavior possible.

Use an email blocklist checker

When you’re noticing increased bounces, suspect that you may have been blocklisted, or just want to practice good email maintenance—you could always manually check each email blocklist. MultiRBL, Barracuda, Spamcop and Spamhaus are just a few of the very many that you can check. However, this is very time-consuming! 

Alternatively, you can use an email blocklist checker tool like Email Insights. These tools can automatically identify any IP blocklists you’re on. MailerCheck also includes other services, like email list verification. Doing this regularly helps to keep your email list healthy and prevents deliverability issues from happening in the first place! 

I’m on a blocklist! 😱 How do I know which one?

When you use MailerCheck to analyze the spamminess of your email content, it will also perform a blocklist check. 

If you have indeed been added to an email blocklist, the tool will include the name(s) of the list(s) you’re present on in its results.

Email blocklist check results in MailerCheck

Here’s a list of all the major IP address blocklists that MailerCheck looks at:

'0spam.fusionzero.com' 'cblless.anti-spam.org.cn', 'ips.backscatterer.org',
'Access.redhawk.org' 'dnsbl-1.uceprotect.net', 'korea.services.net',
'all.s5h.net' 'dnsbl-2.uceprotect.net', 'l2.apews.org',
'bad.psky.me', 'dnsbl-3.uceprotect.net', 'mail-abuse.blacklist.jippg.org',
'b.barracudacentral.org', 'dnsbl.anticaptcha.net', 'misc.dnsbl.sorbs.net',
'bl.mailspike.net', 'dnsbl.dronebl.org', 'new.dnsbl.sorbs.net',
'bl.nosolicitado.org', 'dnsbl.inps.de', 'old.dnsbl.sorbs.net',
'bl.spamcop.net', 'dnsbl.justspam.org', 'zen.spamhaus.org',
'bl.suomispam.net', 'dnsbl.kempt.net', 'psbl.surriel.com',
'bl.tiopan.com', 'dnsbl.sorbs.net', 'rbl.interserver.net',
'black.junkemailfilter.com', 'dnsbl.tornevall.org', 'rbl.realtimeblacklist.com',
'blacklist.sci.kun.nl', 'dnsbl.zapbl.net', 'rbl.schulte.org',
'block.dnsbl.sorbs.net', 'dul.dnsbl.sorbs.net', 'recent.dnsbl.sorbs.net',
'bogons.cymru.com', 'escalations.dnsbl.sorbs.net', 'sip-sip24.invaluement.local',
'cart00ney.surriel.com', 'hil.habeas.com', 'dnsbl.cobion.com',
'cbl.abuseat.org', 'http.dnsbl.sorbs.net', 'ubl.unsubscore.com'

Email blocklisting is designed to protect people from spam. There are various reasons an IP, server or domain name can end up there. Even perfectly legitimate email marketers can find themselves blocklisted. 

Let’s take a look at the different types of listings and their criteria.

Evidence-based listings

These types of listings are the result of hard evidence that points to the IP being involved in sending spam emails. 

This includes:

  • Hacked accounts: The email account is hacked and used by spammers to send large amounts of spam emails. 
  • Spam traps: The sender’s unverified email list contains spam traps. Spam traps are used to identify spam email accounts that haven’t received opt-in consent to send to their “subscribers”. Hitting just one spam trap can cause your email to be blocklisted.
  • Spam complaints: If an ISP, like Gmail, Yahoo or Microsoft, receives a high number of spam complaints about a sender, they can blocklist the sender. Email recipients usually mark emails as spam if they haven’t opted in to receive marketing emails from the sender or if the content is not what they agreed to sign up for. For example, in the event the sender was hacked. 
  • Email spoofing: Email spoofing is when an email sender appears to be a person or business that they are not actually affiliated with. This is a popular method of committing various cyber crimes. 
  • Sending too many emails: Don’t worry, this doesn’t apply to any large amount of emails. It refers to when a sender goes from sending a few outbound emails a day to suddenly sending hundreds or thousands of emails, and thus looks suspicious.  
  • Unhealthy email list: An unhealthy or “dirty” email list is a list that hasn’t been built with genuine opt-in subscribers, and/or hasn’t been properly maintained. It could include old, fake, erroneous, illegally obtained emails, and spam traps, which will all lead to low engagement and deliverability issues.

Technical listings

This type of listing happens because of technical mail server configuration issues. It's a simple mistake, but luckily, also usually easy to rectify. This could be down to incorrect PTR and reverse DNS records, missing DMARC, SPF or DKIM records, or incorrect banner greetings. 

Policy listings

Policy listings occur when the sending IP address belongs to a certain range that is known to break email sending policies. For example, the IP address range has a history of sending substantial amounts of spam emails, or frequently fails to properly handle unsubscribe requests. It also includes IP addresses ranges belonging to end-user devices that should not be sending emails. This helps to protect recipients from potentially infected devices on the network.

See? There’s no need to panic! If you’re a legitimate sender, there are steps you can take to get your email removed from the blocklist, and prevent it from happening again. Here’s how. 

If you’re sending via an ESP or SMTP relay service

ESPs, like MailerLite, and SMTP relay services use a pool of IP addresses which they send emails from. These are known as shared IPs, and they are used by multiple senders. 

Occasionally, the actions of one person have a negative effect on the overall sender reputation, which in turn affects everyone else's deliverability and lands the IP on a blocklist. This rarely happens, as most providers meticulously manage their IP addresses and moderate their user's sending behavior. 

If it does happen, however, it’s on the provider to correct the issue and have the IP removed from the blocklist. In this case, your first port of call is to contact your provider, and they should be able to resolve the situation. 

If you’re sending via your own SMTP server

There’s work to do but if you follow these steps, you should be able to get your IP removed from the block list. 

1. Identify the problem and fix it 

You can run a check using an IP blocklist checker tool, or head to the blocklist website to find your IP address. These will provide you with the reason(s) that your IP address was blocklisted. Next it’s time to fix the issues:

  • Hacked accounts: Regain control of the account, change passwords and put additional security measures in place to protect the server from malware or bots. Clean up any mess created by the hacker. 
  • Spam traps: Run your email list through an email verification tool to identify spam traps (and other potentially damaging emails) and remove them from your list. Take steps to maintain your email list health and avoid spam traps
  • Spam complaints: Remove any subscribers who have not opted-in to your content, and create an opt-in email campaign to confirm those who would like to stick around. Review your newsletter content to re-evaluate whether you’re still providing the type of content you promised to.
  • Email spoofing: Having standard email authentication protocols in place can help protect your business from outbound spoofing attacks (attacks on your customers). Make sure you have properly configured SPF, DKIM and DMARC records
  • Sending too many emails: First, scale back your sendings and then start to warm up your IP reputation gradually. If your email list has grown quickly (and legally), then spread out your sendings, instead of emailing everyone right from the get-go. 
  • Unhealthy email list: Use an email verification service to identify problematic email addresses and remove them from your list. This isn’t a one-time-only task! To keep your email in tip-top shape, improve deliverability, and stay off blocklists, you should regularly perform checks to maintain good list hygiene

2. Scan your computer and network for viruses and malware

You should also ensure that all Operating Systems (OS) are up to date and your network is configured as securely as possible. 

3. Delist your IP address

If you’re confident that you’ve fixed the issues that got you added to the blocklist, it’s time to start the delisting process. Each blocklist has a different procedure, so you should read their instructions carefully, but they will often allow you to submit a removal request. Generally, there are two methods:

  • Self-removal: If you’re on a self-removal list—lucky you! You can do just that. Be warned though that if you are not found to have sufficiently fixed the issues, you’ll be re-added and it will be trickier to remove yourself the next time.
  • Automatic removal: This is time-based and relies on the seriousness of your offense. Lower-level issues will be automatically removed within a couple of weeks, while more serious issues, such as large numbers of spam emails sent, will take longer. If you’ve fixed the issue, it’s just a matter of waiting to be removed. 

If any of these three blocklists ring a bell, that’s because Barracuda, Spamcop and Spamhaus are three of the biggest IP blocklists in use. Here’s how to get delisted from them.

Barracuda

Barracuda allows you to request the removal of your IP address. Once you’ve fixed the issues, fill in the removal request form on Barracuda’s website. Note that multiple requests will not see your IP be delisted faster—in fact, they will be ignored. Submit one request and be patient!

Barracuda email blocklist removal form

Spamcop

Spamcop doesn’t provide the option to submit a removal request. But that’s OK, because if you fix the problems that had your IP flagged, Spamcop will automatically remove you from their email domain blocklist in as little as 24 hours. 

Spamcop ip blocklist removal instructions

Spamhaus

To start the delisting process with Spamhaus, you need to first go to their lookup page. Submit your IP, domain name or hash, and then follow the instructions on how to delist.

Spamhaus IP blocklist checker

You should always provide additional information to support your case where possible. Be open and honest about your situation, and you’ll more likely be granted the removal!

Even if you haven’t been blocklisted, as an email marketer, it’s important to ensure you’re constantly doing everything in your power to prevent it. 

1. Never purchase email lists

Aside from the fact that buying email lists is illegal, they’re extremely bad for business. The people on these lists never consented to be contacted by you. There’s a good chance they’re not interested in your emails, which is sure to result in increased spam complaints. What’s more, these email addresses are unverified and could be full of spam traps, inactive emails and more—which will wreak havoc on your deliverability. 

2. Use an email verification service

Running your email list through a verification tool will identify problematic email addresses so that you can remove them from your list. You’ll avoid spam traps and increase deliverability. 

MailerCheck integrates with tons of popular apps, so you can even verify email addresses in real-time.

3. Keep your email content spam-free

Even with the best intentions, technical mistakes in emails as well as spam-like content and subject lines (including certain words like “buy now” and “free”), can result in your email being filtered into the spam folder. 

Fortunately, when you use MailerCheck’s Email Insights feature for your email address blocklist check, it will also evaluate the quality of your email content so you can be sure that your emails are non-spammy.

4. Stick to using full URLs

URL shorteners are often used by spammers to conceal suspicious links. Use the full URL so the recipient can see what the destination of the link is.

5. Only link to reputable websites

As a legitimate business, you should be doing this anyway, as you’ll have no reason to be sending out dodgy links to subscribers! But linking out to disreputable websites has a negative effect on your email reputation, so be cognizant of the links you share. 

6. Use active/double opt-in confirmation

Make your signup forms clear, and ensure that opt-in consent is active—as in, the subscriber needs to perform an action to opt-in, not to opt-out. Even better, implement double opt-in confirmation so you rest assured that subscribers really want to hear from you. This will also help you to avoid faulty, typoed email addresses. 

7. Make it easy to unsubscribe

Sure, you don’t want subscribers to leave your mailing list, but would you prefer them to mark you as spam instead? Make your unsubscribe button or link easy to find and keep the unsubscribe process simple. 

8. Properly configure your email authentication records

Standard email authentication gives certainty to ISPs that your emails are safe, and it’s fairly easy to set up! 

The goal of blocklists is to protect users from spam—it’s not to stop businesses from sending emails. If you work towards maintaining a healthy, clean email list, ensuring your content isn't spammy, and properly configuring email authentication, you should be able to avoid blocklists.

If you do end up on one however, no sweat, it happens! If it’s because you’ve made a genuine mistake, and not because of questionable practices, you should be able to get delisted in no time. Just remember that IP blocklist removal the second time around is often more tricky—so stick to these best practices to prevent that from happening. 

Do you have any tips for avoiding blocklists or email blocklist removal? Let us know in the comments!

Amy Elliott
I’m Amy, Content Writer at The Remote Company. As a child, I dreamt about writing a book and practiced by tearing pages from an A4 notepad and binding them with sugar paper. The book is pending but in the meantime, I’ve found a passion for telling a different kind of story-the brand story-by writing fun, valuable, human content.