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Email Blacklist Checker

Check if your domain or IP address is listed on major email blacklists (DNSBLs). Being blacklisted can severely impact your email deliverability and sender reputation.

About this tool

Getting blacklisted is one of the most damaging things that can happen to your email program. When your domain or IP appears on a major blacklist like Spamhaus, your delivery rate can drop from 95% to near zero overnight. This checker scans multiple blacklist databases simultaneously so you can catch listings early—before they crater your entire campaign performance.

How email blacklists work

Email blacklists (also called DNSBLs or RBLs) are real-time databases of IP addresses and domains that have been flagged for sending spam. When a mail server receives your email, it checks the sending IP and domain against these lists before deciding whether to accept, filter, or reject the message. The lookup happens via DNS, which makes it extremely fast—a mail server can check dozens of blacklists in milliseconds. Different blacklists have different listing criteria and impact. Spamhaus is the most widely used and a listing there can block delivery to over 3 billion mailboxes worldwide. Smaller lists like SORBS or UCEPROTECT have less reach but can still affect delivery to specific providers.

Why you might be blacklisted (and how to fix it)

The most common cause is high spam complaint rates—if more than 0.1% of your recipients mark your emails as spam, you're in dangerous territory. Other triggers include sending to spam traps (email addresses specifically created to catch spammers), high bounce rates from sending to unverified lists, and compromised accounts sending spam without your knowledge. To fix a listing, you need to identify and resolve the root cause first. Clean your list with our email validator, remove anyone who hasn't engaged in 6+ months, and make sure your SPF and DKIM authentication is properly configured. Only then submit a delisting request—if you request removal without fixing the problem, you'll get listed again within days.

The blacklists that actually matter

Not all blacklists are equal. Spamhaus operates several lists (SBL for known spam sources, XBL for exploited systems, PBL for dynamic IPs) and is checked by the majority of mail servers worldwide. Barracuda maintains a widely-used list that many corporate email systems rely on. SpamCop tracks spam reports from individual users. CBL (Composite Blocking List) focuses on IPs sending spam from bots and malware. A listing on Spamhaus or Barracuda is an emergency—drop everything and fix it. A listing on a smaller, less-used list is concerning but not catastrophic. This checker shows you which specific lists you're on so you can prioritize your response.

Preventing future blacklist listings

Prevention is far easier than recovery. Run every new subscriber through an email validator at signup and reject disposable addresses. Implement double opt-in to confirm subscriber intent. Monitor your bounce rate weekly—keep it under 2%. Watch spam complaint rates in Gmail Postmaster Tools and aim for under 0.05%. If you're warming up a new domain, follow a gradual schedule using our warmup calculator rather than blasting your full list on day one. Set up automated monitoring that alerts you if your domain or IP appears on any blacklist so you can respond before delivery drops significantly.

Frequently Asked Questions

What is an email blacklist?

An email blacklist (also called DNSBL or RBL) is a real-time database of IP addresses and domains identified as spam sources. Mail servers query these databases before accepting incoming email. If the sender's IP or domain is listed, the email may be rejected outright, sent to spam, or heavily filtered. There are over 300 blacklists in operation, but only about 10-15 are widely used enough to significantly affect your delivery.

Which blacklists matter most?

Spamhaus is by far the most impactful—its lists are checked by mail servers handling over 3 billion mailboxes. A Spamhaus SBL listing is essentially a global delivery block. Barracuda is heavily used in corporate environments. SpamCop affects delivery to systems using their filtering. CBL catches botnet-infected IPs. SORBS and UCEPROTECT have moderate reach. Focus your energy on Spamhaus and Barracuda first; smaller lists are less urgent.

How do I get removed from a blacklist?

Every blacklist has its own delisting process, usually through a web form on their site. The critical step most people skip: fix the underlying problem first. If you request delisting without stopping the behavior that triggered it, you'll be re-listed within hours or days, and some blacklists will make your next removal harder. Spamhaus has a self-service removal tool at their website. Barracuda requires filling out a removal request form. Some smaller lists auto-expire after 24-72 hours if the offending behavior stops.

How did I get blacklisted?

The most common causes are: spam complaint rates above 0.1%, sending to spam trap addresses (pristine traps or recycled abandoned addresses), high bounce rates from unverified lists, compromised email accounts sending spam, or sharing an IP address with a spammer on shared hosting. If you're on a shared IP with your ESP, another sender's bad behavior can get the IP blacklisted and affect you too—this is one argument for moving to a dedicated IP once your volume justifies it.

How often should I check for blacklist listings?

For active email senders, check at least weekly. If you're in the middle of a warmup period or recently had deliverability issues, check daily. Set up automated monitoring if possible—most blacklist listings cause immediate delivery drops, and the sooner you catch them, the less damage they do. Some ESPs include blacklist monitoring in their dashboards, but running your own checks gives you an independent view.

Can I prevent my IP from being blacklisted?

You can significantly reduce the risk by maintaining clean lists (validate emails at signup, remove bounces immediately), implementing double opt-in, keeping spam complaints below 0.05%, and never sending to purchased or scraped lists. Monitor your bounce rates and engagement metrics regularly. If you're on a shared IP, consider upgrading to a dedicated IP so other senders' behavior can't affect you. Strong email authentication (SPF, DKIM, DMARC) also helps because it prevents spoofing of your domain.

What's the difference between IP blacklists and domain blacklists?

IP blacklists track the server addresses that send spam—they're tied to your sending infrastructure. Domain blacklists track the domain names used in spam emails (both in the From address and in links within the email body). You can change IPs relatively easily, but your domain follows your brand. Some blacklists like Spamhaus operate both IP-based (SBL) and domain-based (DBL) lists. Being listed on a domain blacklist is arguably worse because it persists even if you switch email providers.

Does being on a blacklist affect all my emails or just marketing?

It affects all email sent from the blacklisted IP or domain—transactional emails (order confirmations, password resets, invoices) get blocked just like marketing emails. This is why many companies use separate IPs or subdomains for transactional and marketing email. If your marketing domain gets blacklisted, your password reset emails still work. This isolation strategy is a best practice for any business that relies on email for both communication and marketing.

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