Is Your Email Blacklisted? Here’s How to Find Out

Key takeaways

• Spam blacklists are used by ISPs and email clients to filter out unwanted messages; getting listed means your emails are diverted to spam or blocked entirely
• Common reasons for getting blacklisted include sending to purchased lists, accumulating spam trap hits, and having a high rate of subscriber spam reports
• Use an aggregate tool like MXToolBox to check whether your IP or domain appears on any major blacklist
• If you’re listed, submit a removal request to the blacklist operator — most require identifying and fixing the root cause before they’ll delist you
• The most effective prevention is a clean, permission-based list combined with regular maintenance; email verification tools like ZeroBounce and Kickbox make this straightforward
• Benchmark Email integrates with deliverability tools to help keep your lists clean and your emails out of the spam folder

Bad news: landing in the spam folder isn’t just an inbox problem. It’s a reputation problem.

A clean sender reputation depends on consistent list maintenance and strong security practices. Regularly remove inactive or invalid addresses, and use a reliable tool to verify emails before sending. This ensures that your content reaches the right inboxes and keeps your sender reputation intact.

Struggling to reach subscribers? Your address may be on a spam blacklist. These can keep your emails out of your subscribers’ inboxes, which, as you might expect, can significantly hinder your email marketing success.

Hundreds of spam blacklists exist, and unfortunately, legitimate email marketers can sometimes get caught in these filters alongside actual spammers. So, how do you know if you’ve been blacklisted? This guide covers what blacklisting is, how to check whether it’s happened to you, and the specific steps to take if it has.

How can I Check if I’m Blacklisted?

With more than 100 blacklists in operation, checking each one manually isn’t practical. Your best starting point is an aggregate tool that checks multiple blacklists at once.

Here are the tools to use:

• MXToolBox: The most commonly used aggregate blacklist checker. Enter your IP address or domain, and it checks more than 100 databases at once. Free and straightforward.
• Barracuda Reputation Block List: Checks against Barracuda’s widely used reputation database. You can also submit a removal request directly from the same page if you’re listed.
• MultiRBL: Another aggregate checker that pulls from a broad range of DNSBL sources. Useful for getting a second read after MXToolBox.
• Sender Score: Rather than a blacklist check, Sender Score gives you a 0-100 reputation rating based on your sending behavior. A low score indicates deliverability problems even if you’re not listed on a specific blacklist.

If you’ve landed on a blacklist, you’re not permanently out of luck. Submit a removal request to the blacklist operator. Most have a web form or a contact address listed. When you reach out, avoid being defensive, even if the listing feels unjust. Explain what caused the issue and what you’ve done to fix it. Some operators will remove you immediately; others may ask you to send a re-permission message to your list or demonstrate that the underlying problem has been resolved.

If your domain or IP is listed at a specific ISP, you’ll need to contact that ISP directly.

What are some Common ISPs?

• Comcast: Visit www.comcastsupport.com/rbl and fill out the online form to submit a delisting request.
• EarthLink: Send an email to blockedbyearthlink@abuse.earthlink.net with the subject line: Blocked [insert your email server’s IP address]. More detail is available at https://earthlink.net/block.
• Gmail/Google Workspace: Review Google’s Bulk Sender Guidelines at https://www.google.com/mail/help/bulk_mail.html, then use the Bulk Sender Contact Form at https://mail.google.com/support/bin/request.py?contact_type=bulk_send to submit your request. Given Gmail’s share of inbox traffic, this one is worth prioritizing.
• Outlook/Hotmail: Visit https://support.msn.com/eform.aspx?productKey=edfsmsbl&ct=eformts and click “Contact Us.”
• Verizon: Visit https://forums.verizon.com/t5/Verizon-net-Email/Blocked-IP-Address-Whitelist-Request/td-p/820064 and fill out the online form.
• Yahoo/AOL: Both are now managed under the same infrastructure. Visit Yahoo Postmaster and click “Problems Delivering Email” to submit a request.
• Mail.ru: Navigate to mail.ru/notspam/ (use a translation tool if needed) and follow the instructions on the page.

Which blacklist databases should I check?

Beyond the aggregate tools above, these individual databases are worth checking directly, especially if you’re seeing deliverability problems and the aggregate results came back clean.

• Spamhaus: One of the most widely used and influential blacklists. Many ISPs check Spamhaus before accepting email. Check your status at https://www.spamhaus.org/lookup.lasso and follow the form to request removal if listed.
• Barracuda Central: Check your IP at https://www.barracudacentral.org/lookups, then submit a removal request at https://www.barracudacentral.org/rbl/removal-request.
• Lashback: Check your IP at https://blacklist.lashback.com/ and submit a removal request directly from the lookup result.
• Invaluement: Check at https://dnsbl.invaluement.com/lookup/ and submit the online form if listed.
• URIBL: Check domain-based listings at https://lookup.uribl.com/.
• Spamcop: For general delisting requests: https://www.spamcop.net/fom-serve/cache/298.html. For bounce message recipients: https://www.spamcop.net/fom-serve/cache/405.html. IP lookup: https://www.spamcop.net/bl.shtml.
• Hostkarma: Submit a removal request at https://ipadmin.junkemailfilter.com/remove.php.

How Can I Avoid Getting Blacklisted?

It’s much easier to stay off of blacklists than to get your address removed once it’s been flagged. Aside from making sure that you don’t fall into spam traps, here are a few other ways to prevent your IP from being blacklisted:

1. Maintain permission-based lists.

Never email someone without their consent. A list built on explicit permission takes longer to grow, but it’s dramatically less likely to generate spam reports, hit spam traps, or accumulate the bounces that attract blacklist attention.

2. Remove addresses that bounce.

When you receive a bounce notification, remove that address. Hard bounces (permanent delivery failures) should be removed immediately. Soft bounces that persist over multiple sends should be removed too. The more you message undeliverable addresses, the more blacklist risk accumulates.

3. Check your contact list for typos.

Quickly scan your list for addresses that look clearly wrong. Better yet, use an email verification tool to handle this automatically. It catches subtle formatting issues that are easy to miss when reviewing manually.

4. Perform routine maintenance.

Prune your email list regularly to remove spam accounts, bounced emails, and incorrect addresses. 

5. Don’t buy emails.

We’re big believers in building your list rather than buying it. When you build, you use tactics that produce quality subscribers who actually want to hear from you. When you buy, you don’t really know what you’re getting. Beyond the quality problem, using a purchased list violates GDPR guidelines and most email platforms’ terms of service, including Benchmark.

6. Verify email addresses.

Before emailing a list that’s been sitting for a while, or any newly acquired list, do what Marc Schenker from The Glorious Company, a copywriting and content marketing agency, does, and run it through an email verification tool. Tools like ZeroBounce and Kickbox check whether addresses are valid, active, and likely to receive email, without you having to send a message to find out. This removes invalid addresses, spam traps, and obvious data quality issues before they affect your reputation.

7. Don’t get marked as spam.

Another way to get blacklisted is when many contacts flag you as spam. This shouldn’t be a concern if you practice proper list etiquette, like maintaining an opt-in-only email list, using email verification software, and providing a clear way to unsubscribe.

8. Perform routine list maintenance.

Prune your list regularly. Remove addresses that haven’t engaged in 6 to 12 months, run re-engagement campaigns before removing long-inactive contacts, and stay on top of unsubscribe requests. A smaller, engaged list consistently outperforms a large, stale one.

Want to take the guesswork out of staying off of blacklists? Use an email marketing tool like Benchmark Email. Our software integrates with various deliverability tools to help you keep your lists clean, ensure your emails reach the inbox, and do everything you can to avoid getting blacklisted. 

Frequently Asked Questions:

What is an email blacklist?

An email blacklist (also called a blocklist or DNSBL) is a real-time database of IP addresses and domains known or suspected to send spam. ISPs, email clients, and corporate mail servers check incoming mail against these lists. If your IP or domain shows up, your emails may be routed to the spam folder or rejected outright.

Why is getting blacklisted bad for email marketers?

For the most part, blacklists do their job well: they keep unwanted and fraudulent messages out of inboxes. The problem is that spam-detection criteria can sometimes catch legitimate marketers. When that happens, your emails stop reaching subscribers, your engagement drops, and your sender reputation takes a hit that can take weeks to repair.

What causes an email blacklisting?

Most listings come back to a handful of issues:

• Spam trap hits. These are addresses planted or repurposed specifically to catch bad sending practices. There are three main types:
  • Typo traps catch lists full of mistyped addresses, like name@gmial.com instead of name@gmail.com. A few won’t hurt you, but many signal poor data hygiene.
  • Pristine traps are addresses that never belonged to a real person. Emailing them strongly suggests a scraped or purchased list.
  • Recycled traps are dormant addresses that ISPs turned into traps after long inactivity. Hitting them means you haven’t pruned inactive contacts.
• High spam complaint rates. When too many subscribers hit “Report spam,” blacklist operators take notice.
• High bounce rates. Repeatedly sending to invalid addresses is a red flag.
• Sudden volume spikes. Jumping from a few hundred emails to tens of thousands overnight looks like spammer behavior.
• Missing email authentication. Without SPF, DKIM, and DMARC, receiving servers have a harder time trusting that your mail is legitimate.
• A compromised account or server. If someone gains access to your sending infrastructure and uses it to blast spam, your IP or domain pays the price.

How do I know if I’ve been blacklisted?

The most reliable way is to run your IP and domain through an aggregate checker like MXToolBox. But there are warning signs that should prompt a check: a sudden drop in open rates, a spike in bounces, or bounce messages that mention a specific blocklist (for example, “rejected due to listing on Spamhaus”).

What’s the difference between an IP blacklist and a domain blacklist?

An IP blacklist flags the server address your emails are sent from. A domain blacklist flags your sending domain or domains that appear in links inside your emails. You can be listed on one without the other, so it’s worth checking both.

Can I get blacklisted because of other senders?

Yes, if you send from a shared IP address. On a shared IP, your reputation is partly tied to everyone else sending from that address. Reputable email service providers like Benchmark actively monitor shared IPs and remove bad actors to protect all senders. High-volume senders may also consider a dedicated IP, which puts reputation fully in their own hands.

How long does it take to get removed from a blacklist?

It depends on the list. Some blacklists remove listings automatically once the problematic activity stops, often within days. Others require a manual removal request and won’t delist you until you’ve fixed the root cause. In most cases, expect anywhere from a few hours to a couple of weeks. Repeat offenders typically face longer listings and stricter delisting requirements.

What should I do first if I find out I’m blacklisted?

Pause any large sends so you don’t make the problem worse. Then identify the cause: review recent bounce rates, complaint rates, list sources, and any changes in sending volume. Fix the issue before submitting a removal request, since most operators will ask what went wrong and what you’ve changed. Requesting removal without addressing the cause usually leads to a quick relisting.

Does email authentication help prevent blacklisting?

Absolutely. SPF, DKIM, and DMARC verify that your emails really come from you, which builds trust with receiving servers. Authentication is also no longer optional for many senders: Gmail and Yahoo require it for bulk senders, and Microsoft has introduced similar requirements for Outlook. Authenticated mail won’t fix a bad list, but unauthenticated mail is much more likely to be filtered or flagged.

What spam complaint rate is too high?

Google recommends keeping your spam complaint rate below 0.1% and never letting it reach 0.3%. That’s roughly one complaint per 1,000 emails as a healthy ceiling. Making it easy to unsubscribe is one of the simplest ways to keep complaints down, because subscribers who can’t find the unsubscribe link often hit “Report spam” instead.

How often should I check if I’m blacklisted?

A monthly check is a good baseline for most senders. Check right away if you notice a sudden drop in deliverability, opens, or clicks. If email is a major revenue channel for your business, consider a monitoring service that alerts you automatically when your IP or domain gets listed.

Will being on one blacklist block all my emails?

Not necessarily. Each mail provider decides which blacklists it uses, so a listing on a smaller blacklist may barely affect delivery, while a listing on a major one like Spamhaus can block mail across many providers at once. Either way, any listing is a signal that something in your sending practices needs attention.

Are “blacklist” and “blocklist” the same thing?

Yes. Many in the email industry now use “blocklist” or “denylist” instead of “blacklist,” but they all refer to the same thing: a list of IPs or domains flagged for sending spam.

How can Benchmark Email help me stay off blacklists?

Benchmark integrates with deliverability and email verification tools to keep your list clean, monitors shared sending infrastructure, and makes it easy for subscribers to unsubscribe instead of marking you as spam. Combined with permission-based list building and regular maintenance, it’s one of the simplest ways to protect your sender reputation.