Troubleshooting Last Updated: February 2026 18 min read

How to Check If Your Email Domain or IP Is Blacklisted

To check if your email is blacklisted, use a free blacklist lookup tool like MXToolbox, MultiRBL, or Google Postmaster Tools. Enter your domain name or sending IP address, and the tool will scan it against 50-100+ known blacklists and return results showing which lists (if any) have flagged you. If you find a listing, identify the root cause, fix it, then request removal through the blacklist operator's delisting process.

What Is an Email Blacklist?

An email blacklist (also called a blocklist or DNSBL) is a real-time database of IP addresses or domain names identified as sources of spam or malicious email. Mailbox providers like Gmail, Yahoo, and Outlook consult these lists when deciding whether to accept, reject, or filter incoming mail.

When your sending IP or domain appears on a blacklist, some or all of your emails may be blocked before they reach recipients. The impact varies depending on which blacklist you are on and which mailbox providers use that list in their filtering decisions.

Blacklists serve a legitimate purpose in the email ecosystem: they help mailbox providers reduce spam and protect users from phishing, malware, and unwanted bulk email. According to industry estimates, blacklist operators collectively help block billions of spam messages daily.

IP Blacklist vs Domain Blacklist: What's the Difference?

Email blacklists come in two primary categories, and understanding the distinction is critical for diagnosing and resolving deliverability issues.

IP-Based Blacklists

IP blacklists target the sending server's IP address. When an IP is listed, all email originating from that server is affected regardless of which domain or sender is using it. This means that if you share a sending IP with other senders (common with shared hosting or shared ESP environments), another sender's bad behavior can get your mail blocked.

Common IP-based blacklists include the Spamhaus SBL, XBL, and PBL, Barracuda BRBL, and SpamCop. If you use dedicated IP addresses, you have full control over the reputation of those IPs. If you are on shared IPs through your email service provider, their abuse team typically handles IP-level listings.

Domain-Based Blacklists

Domain blacklists target your domain name as it appears in email content, headers, or authentication records. A domain listing follows you regardless of which IP or server you use to send. Even if you switch ESPs or move to a new IP range, a domain blacklist listing will continue to affect your deliverability.

The Spamhaus DBL, URIBL, and SURBL are the most widely used domain blacklists. These lists scan the content of spam messages and list domains found in URLs, From addresses, and reply-to headers.

Why You Need to Check Both

A clean IP does not guarantee a clean domain, and vice versa. You may have a perfectly legitimate sending IP but a blacklisted domain because your URL appeared in a phishing email. Or your domain may be clean while your sending IP was listed due to a compromised server on the same network. Always check both your sending IPs and all domains used in your email headers and content.

How Email Blacklists Work

Blacklist operators use several methods to identify problematic senders:

Spam Traps

Spam traps are email addresses specifically designed to catch senders with poor list hygiene. There are three main types:

Pristine spam traps are addresses created solely to catch spammers. They have never belonged to real users and cannot sign up for legitimate mailing lists. If you email one of these addresses, you obtained it through scraping or purchasing lists.

Recycled spam traps are old email addresses that were once valid but have been abandoned and repurposed as traps after 12-18 months of inactivity. Before becoming traps, these addresses return hard bounces, giving legitimate senders an opportunity to remove them.

Typo traps contain common misspellings of popular domains (for example, "gmial.com" instead of "gmail.com"). High volumes of emails to typo addresses indicate poor data collection practices.

Feedback Loops and Complaint Data

When recipients mark emails as spam, that data flows back to blacklist operators through feedback loops. Consistently high complaint rates signal that your mail is unwanted, which can lead to blacklisting. Keeping your complaint rate below 0.1% is essential for staying off blacklists. For strategies on managing this metric, see our guide on how to reduce email spam complaints.

Honeypots

Some blacklists operate honeypot mail servers that accept connections from any sender. These servers monitor for spam-like behavior, such as sending high volumes without proper authentication or attempting to relay mail through open proxies.

Direct Abuse Reports

Network administrators and email users can report spam directly to blacklist operators. Multiple reports about the same sender increase the likelihood of listing.

Major Email Blacklists to Monitor

Not all blacklists carry equal weight. The following lists are widely used by mailbox providers and will have the greatest impact on your deliverability:

Spamhaus

Spamhaus is the most influential blacklist operator in the email industry. They maintain several lists:

A Spamhaus listing will significantly impact your deliverability across most major mailbox providers. For detailed removal timelines, see our guide on how long blocklist delisting takes.

Barracuda Reputation Block List (BRBL)

Barracuda maintains a free blacklist used by organizations running Barracuda security products. IPs are added automatically when they trigger Barracuda's spam detectors or are identified as open proxies or botnet nodes.

SpamCop

SpamCop uses spam reports from users and automated spam trap hits to maintain its list. Listings are time-based and will automatically expire if the spam stops, typically within 24-48 hours of the last reported spam.

SORBS (Spam and Open Relay Blocking System)

SORBS maintains lists covering more than 12 million hosts identified as spam sources, open relays, or otherwise problematic. They operate multiple zone-specific lists targeting different types of abuse.

Invaluement

Invaluement focuses on identifying spam sources that evade other blacklists, particularly snowshoe spam (spam distributed across many IPs to avoid detection) and spam from botnets.

URIBL and SURBL

These lists focus on domains found within spam message content rather than sending IPs. If your domain appears in links inside spam messages, you may be listed even if you did not send the spam yourself.

Free Tools for Checking Blacklist Status

Several free tools allow you to scan your domain and IP addresses against dozens or hundreds of blacklists simultaneously. Below is a detailed walkthrough for each major tool.

MXToolbox Blacklist Check: Step-by-Step Walkthrough

MXToolbox is the most widely used blacklist checking tool and the one we recommend starting with.

  1. Go to mxtoolbox.com/blacklists.aspx in your browser.
  2. Enter your domain name or IP address in the search field. If checking a domain, enter it without "http://" or "www." (for example, enter "yourdomain.com"). For IP addresses, enter the full address (for example, "192.168.1.1").
  3. Click "Blacklist Check" and wait 10-30 seconds for the scan to complete.
  4. Review the results table. MXToolbox checks against 80+ blacklists and displays results in a table format.

Understanding MXToolbox results:

MXToolbox also offers free monitoring alerts. By creating an account, you can set up notifications that email you whenever your domain or IP appears on a new blacklist. This is valuable for catching listings early before they significantly impact deliverability.

MultiRBL: Step-by-Step Walkthrough

MultiRBL checks against the largest number of blacklists of any free tool and provides the most detailed technical results.

  1. Navigate to multirbl.valli.org in your browser.
  2. Select the check type: Choose "IP Address Blacklist Check" for IP lookups or "Domain Blacklist Check" for domain lookups from the homepage options.
  3. Enter your IP or domain in the input field and click "Send."
  4. Wait for the scan to complete. MultiRBL checks against 200+ lists, so the scan may take 30-60 seconds.

Understanding MultiRBL results:

MultiRBL groups results by blacklist category (spam, exploit, policy, etc.), which helps you understand the nature of any listings you find. Pay closest attention to listings in the "spam" and "exploit" categories, as these have the highest deliverability impact.

Google Postmaster Tools: Reputation Monitoring Setup

Google Postmaster Tools does not check traditional blacklists, but it shows you how Gmail specifically views your domain and IP reputation. This is arguably more important than blacklist status for Gmail deliverability.

  1. Go to postmaster.google.com and sign in with a Google account.
  2. Click "Add Domain" and enter your sending domain.
  3. Verify domain ownership by adding the provided DNS TXT record to your domain's DNS settings. Verification typically propagates within a few hours.
  4. Wait for data. Postmaster Tools requires a minimum volume of email to Gmail before it displays data. Most senders begin seeing data within a few days of verification.

Key dashboards to monitor:

Microsoft SNDS: Setup Guide for Outlook Monitoring

Microsoft Smart Network Data Services (SNDS) provides reputation data for how Outlook.com, Hotmail, and Live.com view your sending IPs.

  1. Go to sendersupport.olc.protection.outlook.com/snds and sign in with a Microsoft account.
  2. Click "Request Access" and enter the IP addresses or IP ranges you send email from.
  3. Verify IP ownership. Microsoft sends a verification email to the abuse contact listed in the IP's WHOIS record. If you use an ESP, you may need their help completing this step. Alternatively, some verification methods use DNS records.
  4. Once approved, access the SNDS dashboard to view your sending data.

Key SNDS metrics:

SNDS also provides a Junk Email Reporting Program (JMRP) that sends you copies of complaint reports in real time, similar to a feedback loop. Enrolling in JMRP is free and provides valuable data for identifying which messages generate complaints.

Step-by-Step Guide: Checking Your Blacklist Status

Step 1: Identify Your Sending IPs and Domains

Before checking blacklists, gather the information you need to query:

If you use an email service provider, check their documentation or support team for your assigned sending IPs. Many providers offer dedicated IP addresses for high-volume senders. For shared IP senders, ask your ESP which IP pools your mail routes through.

Step 2: Run a Multi-Blacklist Scan

Start with MXToolbox for a quick scan, then use MultiRBL for a more comprehensive check. Enter each domain and IP address separately, as results differ between them. Run checks for:

Step 3: Interpret the Results

A clean result means none of the checked blacklists have flagged your domain or IP. Your deliverability issues, if any, likely stem from other factors such as poor sender reputation, authentication failures, or content filtering.

If you appear on one or more blacklists, note:

A listing on a major blacklist like Spamhaus requires immediate attention. Listings on smaller or less influential blacklists may have minimal impact but should still be investigated.

Step 4: Check Individual Blacklist Details

For each listing found, visit the blacklist operator's website to understand:

This information is critical for both resolving the current listing and preventing future ones. For a complete walkthrough of the removal process, see our guide on how to get removed from an email blacklist.

What to Do If You Find Your Email Is Blacklisted

Finding your domain or IP on a blacklist requires immediate, structured action. Follow this checklist in order:

  1. Assess the severity. Determine which blacklists you are on. Spamhaus, Barracuda, and SpamCop listings require urgent action. Minor blacklist listings can be addressed on a standard timeline.
  2. Identify the root cause. Check your bounce logs for patterns: are hard bounces spiking? Did complaint rates jump above 0.1%? Was there a recent list import or campaign to a purchased list? Look for compromised accounts or servers sending unauthorized mail.
  3. Stop the harmful sending immediately. If a specific campaign or list segment triggered the listing, pause it. If your server is compromised, take it offline and secure it before sending anything else.
  4. Clean your mailing list. Remove all hard bounces, known spam traps, unengaged subscribers (no opens or clicks in 6+ months), and addresses from any purchased or scraped sources.
  5. Verify your authentication. Confirm that SPF, DKIM, and DMARC are all passing at 100%. Authentication failures compound blacklist problems and make delisting harder.
  6. Submit delisting requests. Once you have identified and fixed the root cause, follow each blacklist's removal process. For detailed instructions and expected timelines, see our complete blacklist removal guide and our guide on how long delisting takes by blacklist.
  7. Monitor for relisting. After delisting, monitor daily for at least two weeks. If you are relisted quickly, the root cause has not been fully resolved.
  8. Document everything. Keep records of what caused the listing, what you fixed, and when you were delisted. This documentation helps if you need to contact blacklist operators again.

Do Not Request Delisting Before Fixing the Problem

Submitting a removal request without resolving the underlying cause will result in relisting, often within hours. Worse, repeated premature delisting requests can flag your domain as a repeat offender, making future removals harder and slower. Fix first, then request removal.

How to Get Delisted from Email Blacklists

General Delisting Process

  1. Identify the root cause: Do not request delisting until you understand why you were listed. Requesting removal without fixing the underlying problem will result in relisting, often within hours.
  2. Fix the issue: Common fixes include removing spam traps and invalid addresses from your list, implementing proper email authentication (SPF, DKIM, DMARC), securing compromised servers or accounts, and stopping any sending practices that violate the blacklist's policies.
  3. Submit a delisting request: Most blacklists provide a web form for removal requests. Include your IP address or domain, explanation of what caused the listing, and steps you have taken to prevent recurrence.
  4. Wait for processing: Delisting typically takes 24-72 hours depending on the operator. See our blocklist delisting timeline guide for specific timeframes by blacklist.

Delisting from Specific Blacklists

Spamhaus: Use the Spamhaus Blocklist Removal Center at check.spamhaus.org. Enter your IP or domain, and follow the provided instructions. Spamhaus removal is free. Any service offering to remove you for a fee is a scam.

Barracuda: Submit a removal request through barracudacentral.org. You will need to demonstrate that the issue has been resolved.

SpamCop: Listings expire automatically 24-48 hours after the last spam report. Ensure you have stopped the spam and wait for automatic delisting.

Microsoft: Use the Outlook.com sender support page at sender.office.com to submit a delisting request. Include your IP address and details about what you have fixed. Microsoft typically responds within 48 hours.

For a comprehensive walkthrough of removal procedures for each major blacklist, see our dedicated guide on how to get removed from an email blacklist.

How Often Should You Check for Blacklisting?

Regular monitoring catches blacklist listings early before they cause widespread deliverability damage. Here is a recommended monitoring schedule based on your sending volume and risk level:

High-Volume Senders (100,000+ emails per month)

Medium-Volume Senders (10,000-100,000 emails per month)

Low-Volume Senders (under 10,000 emails per month)

Set Up Automated Alerts

Manual checking is a safety net, but automated alerts should be your primary detection method. MXToolbox offers free blacklist monitoring with email alerts. Google Postmaster Tools shows daily reputation data. Configure both so you are notified of problems the same day they occur rather than discovering them days or weeks later when the damage to your sender reputation is harder to reverse.

When to Run an Immediate Check

Beyond your regular schedule, check your blacklist status immediately whenever you observe:

How to Prevent Future Blacklisting

Build Lists Through Opt-In

Never purchase, rent, or scrape email lists. These lists contain spam traps, invalid addresses, and people who have not consented to receive your email. Use double opt-in (confirmation email) to verify new subscribers are real and genuinely want your messages.

Maintain List Hygiene

Remove hard bounces immediately after they occur. A hard bounce today could become a recycled spam trap in 12-18 months. Implement a sunset policy for unengaged subscribers: if someone has not opened or clicked in 6-12 months, remove them or run a re-engagement campaign.

Validate email addresses at the point of collection to catch typos before they enter your database.

Implement Proper Authentication

Configure SPF, DKIM, and DMARC for all domains and subdomains you use for sending email. Authentication failures are a common trigger for blacklisting. Use tools like Google Postmaster Tools and Microsoft SNDS to monitor your authentication success rates.

Monitor Complaint Rates

Keep your spam complaint rate below 0.1%. Gmail and Yahoo both enforce this threshold for bulk senders. High complaint rates indicate your recipients do not want your email, which blacklist operators interpret as spam. For actionable tactics, see our guide on how to reduce email spam complaints.

Secure Your Infrastructure

Compromised mail servers and websites can be used to send spam without your knowledge. Keep all software updated, use strong passwords, and monitor your sending patterns for unusual activity. If your server is sending spam due to a security breach, blacklists will not care that it was not intentional.

Warm Up New IPs Gradually

When you start sending from a new IP address, begin with low volume and increase gradually over 4-8 weeks. Sudden high-volume sending from a new IP is a spam indicator that can trigger blacklisting.

Tools for Ongoing Monitoring

We recommend checking your blacklist status regularly, not just when you suspect a problem. The tools below form a complete monitoring stack:

ToolBest ForCostCheck Frequency
MXToolboxMulti-blacklist scanning, alertsFree (basic), paid plans availableDaily or automated alerts
MultiRBLBroadest blacklist coverage (200+)FreeWeekly or monthly
Google Postmaster ToolsGmail reputation and spam ratesFreeDaily or weekly
Microsoft SNDSOutlook/Hotmail reputationFreeWeekly
DNSCheckerQuick IP blacklist checksFreeAs needed

Set up automated monitoring to catch blacklistings quickly. The faster you detect a listing, the less damage it will do to your overall deliverability. Most blacklist damage occurs in the first 24-48 hours before you are even aware of the listing, which is why automated alerts are far more effective than periodic manual checks.

Frequently Asked Questions

How long does it take to get removed from an email blacklist?
Removal timing depends on the blacklist. Some lists like SpamCop delist automatically within 24-48 hours after the spam stops. Others like Spamhaus require manual review and typically process requests within 24 hours. If your listing involves serious violations or repeated offenses, removal may take longer or require additional documentation. For specific timelines by blacklist, see our blocklist delisting timeline guide.
Will being on one blacklist get me listed on others?
Not directly. Each blacklist operates independently with its own detection methods and listing criteria. However, the same behavior that caused one listing (spam trap hits, high complaints, compromised server) may trigger listings on multiple blacklists simultaneously. Fixing the root cause should prevent new listings across all blacklists.
Can I send email while I am on a blacklist?
You can continue sending, but some or all of your messages may be blocked or filtered to spam depending on which blacklist you are on and which mailbox providers your recipients use. We recommend reducing volume or pausing campaigns to Gmail and other major providers until you are delisted to avoid further reputation damage.
Do I need to check blacklists if I use an email service provider?
Yes. While reputable email platforms monitor their shared infrastructure, you are still responsible for your domain reputation. Your domain can be blacklisted even if your sending IP is clean. Additionally, if you are on dedicated IPs, you bear full responsibility for the reputation of those addresses.
How do I know which blacklist is causing my deliverability problems?
Check your bounce messages for clues. Many mailbox providers include the blacklist name in rejection messages. Additionally, use Google Postmaster Tools and Microsoft SNDS to see how those providers specifically view your reputation. A multi-blacklist scan with MXToolbox will reveal all current listings.
Is my email blacklisted if emails go to spam?
Not necessarily. Emails landing in spam can result from many factors including poor sender reputation, missing authentication (SPF, DKIM, DMARC), high complaint rates, or content filtering. Blacklisting is one possible cause, but you should check your blacklist status alongside your authentication setup and complaint rates to identify the actual issue.
What is the difference between an IP blacklist and a domain blacklist?
An IP blacklist targets the sending server's IP address, while a domain blacklist targets your domain name regardless of which IP sends the mail. IP blacklists affect all mail from that server, while domain blacklists follow your domain across any sending infrastructure. You need to check both your IP addresses and domain names for complete coverage.

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