Your emails are bouncing, clients say your messages are in their spam folder, or a bounce notice mentions "Spamhaus" or "blocked." You're probably wondering whether your domain has landed on an email blacklist (also called a blocklist or DNSBL).
It happens to legitimate businesses all the time, usually because of a compromised mailbox, a misconfigured domain, or a burst of spam complaints. The good news is that most listings can be diagnosed and removed within days once the cause is fixed. This guide walks you through checking your status, finding the cause, getting delisted, and staying off blacklists for good.
If emails are going to spam but you're not listed anywhere, start with our broader guide on why emails go to spam and how to fix it; blacklists are only one possible cause.
Check your sending IPs and domain with a multi-list tool like MXToolbox or MultiRBL. If you're listed, find and fix the root cause first (usually a hacked account, bad list, or missing authentication), then request removal from each list following its own process. Afterwards, monitor complaint rates and authentication continuously so it doesn't happen again.
What You Need Before Starting
Your sending IPs and domains. Include your email provider's servers and every third-party service that sends as your domain (newsletter tools, CRMs, invoicing apps, website contact forms).
Access to your DNS settings, so you can check and fix SPF, DKIM, and DMARC.
Bounce messages. The exact wording of a rejection often names the blacklist and links to its lookup page. Save a few.
Admin access to your email accounts and logs, to look for unusual sending.
Monitoring accounts with Google Postmaster Tools and Microsoft SNDS (both free).
One important distinction: if you use a hosted email provider, your everyday mail usually goes out from the provider's IP addresses. If one of those IPs is listed, that's primarily the provider's job to resolve, so contact their support. What you control is your domain's reputation, your accounts' security, and your authentication records. Knowing which is listed saves you a lot of wasted effort.
Step 1: Check the Major Blacklists
Enter your sending IP and your domain into a multi-list checker such as MXToolbox Blacklist Check or MultiRBL. These query dozens of lists at once. Note every "Listed" result, but don't treat them all equally. The lists that actually affect delivery at scale include:
Spamhaus (SBL, XBL, CSS for IPs; DBL for domains), the most widely used.
Barracuda (BRBL), used by many corporate gateways.
SpamCop, which lists IPs based on user spam reports.
URIBL and SURBL, which list domains that appear in message content, including links in your signature or body.
Many minor or obscure lists have little real-world impact. Fix the cause and focus your delisting effort on the major ones first. Note that SORBS, often mentioned in older guides, was shut down in 2024, so you can ignore stale results or advice referring to it.
Pro tip: Check both your IP and your domain. Some lists track IPs and others track domains. A domain can also be listed because of a URL it contains, for example a link shortener or a compromised website linked in your signature.
A note on Google Postmaster Tools: it doesn't show blacklist status, and Google retired its old "Bad / Low / Medium / High" domain and IP reputation dashboards in 2025. It's still valuable for spam complaint rates, authentication results, and compliance with Gmail's sender requirements, which is why it belongs in Step 5.
Step 2: Identify the Root Cause
Blacklist operators will reject removal requests if the problem is still happening, so diagnosis matters. The most common causes are:
A compromised account. Attackers use one stolen password to send thousands of spam messages. Look for sudden spikes in outbound volume, messages in Sent you don't recognize, new forwarding rules, or logins from unusual locations. Our guide to phishing protection and TLS encryption covers how these compromises usually start.
Leaked app credentials. A website contact form or plugin sending through SMTP with a stolen password can blast spam without anyone logging in. If you're unsure which tools send as your domain, see IMAP vs SMTP vs API integrations.
Purchased, scraped, or stale lists, which hit spam traps and generate complaints.
Missing or broken SPF, DKIM, or DMARC, which makes your mail look suspicious and your domain easy to spoof.
A sudden change in sending patterns, like a large campaign from a brand-new domain or IP with no warm-up.
Forgotten accounts belonging to former employees, which are prime targets for takeover. (See our guide on what to do with an employee's email when they leave.)
Most blacklist lookup pages tell you why you were listed, for example "spam trap hits" or "compromised host." Read the listing details carefully and write down what you find; you'll need it for your removal requests.
Step 3: Fix the Underlying Problem
Match the fix to the cause:
Compromised account: reset the password, sign out all sessions, enable two-factor authentication, remove any rules or forwarding the attacker added, and check the user's device for malware. Then check every other account for signs of the same attack.
Leaked app credentials: rotate the password or API key, and give each app its own credential so a leak can't take everything down.
Bad lists: stop sending to purchased or scraped addresses immediately, remove hard bounces, and switch to confirmed opt-in.
Authentication gaps: publish an SPF record listing every legitimate sender, enable DKIM signing, and add a DMARC record starting at
p=noneso you can monitor before moving toquarantineorreject. Our guide on domain authentication and why business emails land in spam walks through each record.Mixed traffic: separate bulk marketing from your day-to-day and transactional email, ideally using a subdomain or dedicated service for campaigns, so one bad send can't drag down your whole domain.
Then watch outbound volume for a few days to confirm the spam has actually stopped.
Pro tip: Send a test message to a checker like Mail-Tester to confirm SPF, DKIM, and DMARC all pass before you request delisting.
Step 4: Request Removal From Each Blacklist
Each list has its own process, and some remove you automatically:
Spamhaus: look up your IP or domain in the Spamhaus removal center. The listing type (SBL, XBL, CSS, DBL) determines the process; XBL listings usually point to an infected or compromised device, and CSS listings to low-reputation sending patterns. Some are self-service once fixed; others need a ticket explaining what you changed.
Barracuda: submit the removal form on Barracuda Central with your IP and a short explanation.
SpamCop: listings typically expire automatically once reports stop, so fixing the source is the main task.
URIBL / SURBL: use their lookup pages, which explain how to request removal for a listed domain.
Keep requests short and factual: the listed IP or domain, what caused the listing, and the specific steps you took to fix it. Log each submission with the date. Many lists process requests within a day or two, but timelines vary, and repeat listings are usually handled more slowly.
Pro tip: Never pay a third party who promises "guaranteed delisting." Legitimate major blacklists don't charge for removal.
Step 5: Monitor and Prevent Relisting
Getting delisted is half the job. To stay off:
Monitor continuously. Set up automated blacklist monitoring (MXToolbox and similar services offer alerts), plus Google Postmaster Tools for Gmail spam rates and Microsoft SNDS for Outlook.com traffic.
Keep complaint rates low. Google asks bulk senders to keep reported spam below 0.1% and to avoid ever reaching 0.3%.
Check authentication regularly. Adding a new tool that sends as your domain often breaks SPF without anyone noticing.
Practice list hygiene. Remove bounces and long-inactive subscribers, and make unsubscribing easy.
Secure every account. Two-factor authentication for everyone, and prompt closure of accounts when people leave.
Use feedback loops where available, such as Yahoo's Complaint Feedback Loop and Microsoft's JMRP, to learn who's marking you as spam.
For the full checklist, see our guide to email deliverability best practices.
Example: Recovering From a Compromised Account
The following is an illustrative scenario.
An online retailer notices order confirmations bouncing on a Monday morning. A blacklist check shows its sending IP on Spamhaus and Barracuda, and its domain on one URI list. The sent logs reveal the cause: over the weekend, a staff account with a reused password sent thousands of spam messages.
The team resets the password, enables 2FA across the company, removes a forwarding rule the attacker had added, and discovers their domain had never published a DMARC record. They add SPF, DKIM, and DMARC, confirm spam has stopped, then submit removal requests explaining each fix. Most listings clear within a couple of days; one takes about a week. They then move marketing campaigns to a separate subdomain and set up blacklist alerts so they'd know within hours next time.
How to Choose Monitoring Tools
Match tools to how much email you send:
Need | Good options | Cost |
|---|---|---|
Occasional manual checks | MXToolbox, MultiRBL | Free |
Gmail and Outlook insight | Google Postmaster Tools, Microsoft SNDS | Free |
Automated blacklist alerts | MXToolbox monitoring and similar services | Free to low |
Inbox placement testing | GlockApps and similar seed-testing tools | Paid |
High-volume senders | Enterprise deliverability platforms (e.g. Validity) | $$$ |
For most small businesses, free tools plus good security habits are enough. The bigger decision is your email platform: look for guided SPF, DKIM, and DMARC setup, two-factor authentication, and monitoring for suspicious account activity, since compromised accounts are one of the most common reasons businesses get listed.
How Email Blacklists Work
Email blacklists are real-time databases of IP addresses and domains associated with spam or abuse. Receiving mail servers query them as messages arrive, and a match can mean outright rejection or a trip to the spam folder.
Operators add entries in different ways: spam traps (addresses that should never receive mail), user complaint reports, detection of infected machines, and analysis of sending patterns. Each list has its own criteria and removal policy, which is why being listed on one doesn't mean you're listed on all.
Delisting stops the immediate blocking, but mailbox providers like Gmail and Outlook also track reputation internally, and that recovers gradually as you send clean, wanted mail. That's why prevention (authentication, list hygiene, and account security) pays off far more than any cleanup. Modern filtering is also increasingly driven by recipient engagement and machine learning, as we explore in how AI is changing the inbox.
Common Mistakes
Requesting removal before fixing the cause. You'll be rejected or quickly relisted, and repeat listings are harder to clear.
Panicking over minor lists. Focus on the lists that actually block your mail.
Ignoring authentication. Missing SPF, DKIM, or DMARC hurts deliverability and lets others spoof your domain.
Sending to purchased or scraped lists. One of the fastest routes onto a blacklist.
Securing only the account that was hacked. Attackers often have more than one password; check them all and enforce 2FA.
Mixing marketing and business mail on one domain and IP. A bad campaign shouldn't be able to block your invoices.
FAQ
How do I know if my domain is blacklisted?
Enter your domain and sending IP into a multi-list checker like MXToolbox or MultiRBL. Bounce messages that name a blocklist are also a strong clue.
What should I do first if I'm listed?
Find out why. Check the listing details, look for compromised accounts and unusual sending, then fix the cause before requesting removal.
How long does delisting take?
Once the issue is fixed, many listings clear within a day or two, and some expire automatically. Repeat listings or complex cases can take a week or more.
My provider's IP is listed, not my domain. What do I do?
Contact your email provider. Shared sending IPs are managed by the provider, which is usually best placed to request removal.
What's the difference between an IP blacklist and a domain blacklist?
IP lists track the servers sending mail; domain lists track domain names, either in your From address or in links inside your messages. Changing IPs won't fix a domain listing.
Can a blacklist hurt me even if I never send marketing email?
Yes. A single compromised mailbox sending spam can get your domain or IP listed, which affects everyday business email.
Can I pay to get delisted faster?
Major blacklists don't charge for removal. Be wary of anyone selling "guaranteed" delisting.
How can I prevent blacklisting?
Authenticate your domain, send only to people who opted in, secure every account with 2FA, separate marketing from business mail, and monitor continuously.
Keep Your Domain's Reputation Clean With NevTan Mail
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Related reading: Why emails go to spam · Email deliverability best practices · All articles
