Blacklist Lookup — Check Domain & IP Address Reputation Instantly

If your emails are landing in spam folders, if your website is being blocked by security filters, or if your server’s traffic is being rejected without explanation, there is a very real possibility that your domain or IP address has been added to a blacklist. Blacklisting is one of the most damaging and least visible problems a website owner or email administrator can face — and it can happen to anyone, often without any warning. Our Free Blacklist Lookup checks your domain or IP address against more than 20 major spam and security blacklists — including Spamhaus, SpamCop, SURBL, and Barracuda — and returns a complete reputation report with a reputation score and specific recommendations for getting delisted.

No account required. No payment. No installation. Enter any domain or IP address and get your complete blacklist check report in seconds.

What Is This Free Blacklist Lookup?

This is an online reputation checking tool that scans any domain name or IP address you enter against more than 20 major spam and security blacklist databases. It checks each blacklist simultaneously and reports back whether your domain or IP is listed, clean, or flagged across each database.

When you run a check, the tool gives you:

• Reputation Score — an overall rating of your domain or IP’s current reputation
• Blacklist Status — clear listed or not listed results for each database checked
• Domain or IP Check — separate input modes for checking domain names or IP addresses
• Spamhaus Check — one of the world’s most widely used anti-spam databases
• SpamCop Check — real-time spam reporting network blacklist
• SURBL Check — spam URI reputation block list focused on web-based spam
• Barracuda Check — email and network security blacklist used by enterprise filters
• 20+ Additional Blacklists — comprehensive coverage of major DNS-based blacklists
• Blacklist Check Results Table — detailed per-blacklist pass/fail status
• Actionable Recommendations — specific steps to get delisted from each flagged database
• Export Report — download your complete blacklist scan report
• Copy Summary — copy key findings to your clipboard

What Is a Blacklist?

A blacklist — also called a blocklist, DNSBL (DNS-based Blackhole List), or RBL (Real-time Blackhole List) — is a database of IP addresses, domain names, or email servers that have been identified as sources of spam, malware distribution, phishing attacks, or other abusive activity.

These databases are maintained by cybersecurity organizations, email security providers, and anti-spam companies. Mail servers, internet security systems, web hosting providers, and network operators around the world query these blacklists to decide whether to accept, block, or flag traffic coming from a particular IP address or domain.

How blacklists work in practice: When an email server receives an incoming message, it automatically checks the sending server’s IP address and the domain in the email against various blacklists. If a match is found — meaning the IP or domain is listed — the receiving server can reject the email outright, quarantine it to a spam folder, or flag it for additional scrutiny. This happens invisibly and automatically, thousands of times per second across the global email infrastructure.

For websites, similar checks happen through web security filters, browser safe browsing systems, and network-level content filters. A blacklisted domain can be blocked by these systems, preventing users from accessing the website or triggering security warnings in their browsers.

The Four Major Blacklists This Tool Checks

🚫 Spamhaus — The World’s Most Widely Used Anti-Spam Resource

What it is: Spamhaus is a non-profit cybersecurity organization that maintains some of the most widely used and respected spam and malware blacklists in the world. Their databases are queried billions of times per day by mail servers, ISPs, and security systems globally.

Spamhaus maintains several key blacklists:

SBL (Spamhaus Block List) Lists IP addresses verified as belonging to known spammers, spam gangs, or spam support services. Being listed on the SBL means your IP has been directly associated with spam activity.

XBL (Exploits Block List) Lists IP addresses of compromised computers, open proxies, and systems running malware that are being used to send spam without the owner’s knowledge. An XBL listing often means a server or device on your network has been hacked or infected.

PBL (Policy Block List) Lists IP address ranges that should not be directly delivering email to mail servers — primarily residential and dynamic IP ranges from ISPs that are intended for general internet access but not for running mail servers. A PBL listing does not necessarily mean your IP is involved in spam — it may simply be in a residential IP range.

DBL (Domain Block List) Lists domain names found in spam email — either as the sender domain, a URL embedded in spam content, or as infrastructure supporting spam campaigns.

Why Spamhaus matters: Spamhaus is used by virtually every major email provider and enterprise mail security system. A listing on Spamhaus — particularly the SBL or XBL — can block your email from reaching recipients at Gmail, Outlook, Yahoo, and millions of corporate email addresses.

🔒 SpamCop — Real-Time Spam Reporting Network

What it is: SpamCop is a spam reporting service that processes spam complaints submitted directly by email users. When users report spam they receive, SpamCop analyzes the reported messages, traces them back to the source IP addresses, and adds those IPs to its Blocking List (SCBL) if a sufficient volume of complaints is received from that source.

How SpamCop listings work: SpamCop’s listing is time-sensitive — IPs are listed based on recent spam activity and delist automatically once the volume of incoming complaints drops below the threshold. A SpamCop listing indicates that a significant volume of spam was recently traced back to the listed IP address.

Who uses SpamCop: ISPs, corporate mail systems, and email hosting providers around the world use SpamCop as one input in their spam filtering decisions. While SpamCop is not as universally implemented as Spamhaus, a listing can still significantly affect email deliverability.

Common causes of SpamCop listings:

• A compromised server sending spam without the owner’s awareness
• A customer account on shared hosting sending bulk email
• A mail server being used as an open relay

🌐 SURBL — Spam URI Reputation Block List

What it is: SURBL (Spam URI Reputation Block List) is different from most blacklists in a fundamental way — instead of listing the IP addresses of mail servers that send spam, it lists domains that appear as links within spam email content itself.

When a spam email contains a link — “Click here to claim your prize at yourdomain.com” — and that link is reported repeatedly across spam submissions, SURBL adds the linked domain to its database. Any email containing a link to a SURBL-listed domain triggers filters that use SURBL data.

Why SURBL matters: SURBL is primarily relevant for your domain’s reputation in the email ecosystem. If your domain is found embedded in spam emails — even if you did not send those emails — it may be listed on SURBL. This can happen if spammers use your domain name in their campaigns, or if your website has been compromised and is being used in spam content.

Impact of a SURBL listing: Emails containing links to your domain may be blocked or spam-filtered by systems using SURBL data, even if those emails are coming from completely legitimate sources. This can affect newsletters, transactional emails, and marketing campaigns.

📧 Barracuda — Enterprise Email and Network Security

What it is: Barracuda Networks is a cybersecurity company that maintains its own email reputation database — the Barracuda Reputation Block List (BRBL). Barracuda’s email security appliances and cloud services are widely deployed in enterprise environments, government agencies, and educational institutions around the world.

What the Barracuda blacklist covers: Barracuda maintains separate reputation databases for both IP addresses and domains. IPs and domains are listed based on analysis of email traffic flowing through Barracuda’s global security network, combined with automated reputation scoring and manual review.

Why Barracuda matters: Barracuda’s security products are particularly prevalent in enterprise and institutional environments. A Barracuda listing can block your email from reaching recipients at companies, schools, and government agencies that use Barracuda security products — often without any visible error to the sender.

How Barracuda delisting works: Barracuda provides a public delisting request form at its website. If your IP or domain has been legitimately misidentified as a spam source, you can submit a delisting request with documentation of the issue. Barracuda’s review team evaluates requests and typically responds within 24 to 48 hours.

The 20+ Blacklists — Why Comprehensive Coverage Matters

Beyond the four major blacklists above, this tool checks your domain and IP against more than twenty additional specialized databases. Here is why broader coverage matters:

Different blacklists serve different audiences Some blacklists are used by specific ISPs, regional providers, or specialized email systems that may not query the major four. A listing on a smaller but specialized blacklist can still block your email from reaching recipients who use providers that rely on that database.

Specific threat categories have specialized databases Some blacklists focus on specific types of threats — malware distribution, phishing domains, botnet command-and-control servers, or specific geographic spam sources. Being checked against a broad set of specialized databases gives you a more complete picture of your overall reputation across the security ecosystem.

Your reputation is the sum of all listings, not just the biggest one A clean Spamhaus check does not mean you are universally trusted. If you are listed on several smaller blacklists simultaneously, your cumulative reputation impact can be significant — affecting deliverability to a meaningful portion of email recipients even without a major blacklist listing.

Understanding Your Reputation Score

The reputation score is an overall assessment of your domain or IP’s standing across all the blacklists checked. It gives you an immediate, at-a-glance indication of how serious your current situation is:

Reputation Score	Status	What It Means
90 – 100	Excellent	Clean across all or nearly all blacklists — no action needed
70 – 89	Good	Minor or low-priority listings — monitor and review
50 – 69	Fair	Some listings detected — investigate and begin delisting process
30 – 49	Poor	Multiple listings — significant deliverability impact — urgent action
Below 30	Critical	Listed on major blacklists — email delivery severely impaired — immediate action required

Use this score as your starting point, then review the detailed per-blacklist results to understand exactly which databases have flagged your domain or IP and prioritize your delisting efforts accordingly — major blacklists like Spamhaus first, then smaller ones.

Why Domains and IP Addresses Get Blacklisted

Understanding the most common causes of blacklisting helps you both fix the current problem and prevent future listings. Here are the most frequent reasons:

🦠 Compromised Server Sending Spam

The most common cause of IP blacklisting is a server being hacked or compromised and used by attackers to send spam at scale — without the server owner knowing it is happening. This can occur through:

• Exploited software vulnerabilities (outdated WordPress plugins, unpatched server software)
• Compromised user accounts (weak passwords, phishing attacks)
• Malware installed on the server
• Open mail relay configurations that allow anyone to use the mail server

When a server is compromised, it can send tens of thousands of spam messages in hours. Blacklists that monitor spam volume can detect and list the IP almost immediately.

Signs your server may be compromised:

• Unusual outbound email volume in your hosting logs
• Bounce messages from addresses you never emailed
• Server performance degradation without explanation
• Unusual processes running on your server

📨 Bulk Email Without Proper Opt-In

Sending large volumes of email — even legitimate marketing email — to recipients who did not explicitly opt in to receive it can result in a flood of spam complaints. If enough recipients mark your emails as spam, those complaints feed into blacklisting systems.

Email providers like Gmail and Outlook track what percentage of your emails are marked as spam by recipients. Consistently high complaint rates lead to filtering and eventual blacklisting even for email that started as legitimate marketing.

Best practices to avoid complaint-based blacklisting:

• Only email people who explicitly opted in and confirmed they want to hear from you
• Include a clear, working unsubscribe link in every email
• Remove unsubscribers immediately — do not continue emailing people who have asked to stop
• Segment your list and only send relevant content to each group

🎣 Phishing or Malware Association

If your domain or website is associated with phishing attacks or malware distribution — either because your site was hacked and used to host malicious content, or because attackers spoofed your domain in phishing emails — your domain can be listed on security-focused blacklists quickly.

Phishing and malware blacklists update rapidly and are implemented widely across browsers (Google Safe Browsing, Microsoft SmartScreen), email clients, and network security systems.

📋 Previous Owner’s Bad Reputation

If you purchased a domain, registered an expired domain, or took over an IP address previously associated with spam or malicious activity, you may inherit the previous owner’s blacklist listings. The blacklist databases hold records based on the domain or IP itself — not the current owner.

This is why checking blacklist status is an essential step when acquiring any domain or when a hosting provider assigns you an IP address from their pool.

🔓 Open Mail Relay

An open relay is a mail server configured to accept and forward email from any sender to any recipient — without authentication. Spammers actively scan the internet for open relays and exploit them to send massive volumes of spam, causing the relay’s IP to be blacklisted rapidly.

Any mail server should require authentication before accepting mail for relay. If your mail server is configured as an open relay — even accidentally — it will almost certainly be listed on multiple blacklists very quickly.

📊 Poor Email List Hygiene

Sending email to invalid addresses, long-inactive addresses, or spam trap addresses causes high bounce rates and spam trap hits — both of which feed into blacklisting systems.

Spam traps are email addresses that legitimate companies would never email — they are created specifically to catch senders with poor list hygiene or those who harvest email addresses without permission. Hitting a Spamhaus-operated spam trap can result in an immediate listing.

How to Use This Free Blacklist Lookup

Running your blacklist check takes just a few seconds. Here is the exact process:

Step 1 — Choose Your Check Type

Click the Domain Name tab to check a domain’s reputation, or the IP Address tab to check a specific IP address.

When to check a domain: When diagnosing issues with your website’s reputation, email deliverability problems related to your sending domain, or checking whether a competitor or suspicious website is blacklisted.

When to check an IP address: When your mail server is being rejected, when checking whether a specific outbound mail server IP is listed, or when investigating a server that may have been compromised.

Step 2 — Enter Your Domain or IP Address

For domain checks: enter the domain name without https:// — for example: yourdomain.com For IP checks: enter the full IPv4 address — for example: 203.0.113.45

Step 3 — Click “Check Blacklist”

Click the 🔍 Check Blacklist button. The tool simultaneously queries all 20+ blacklist databases and compiles your complete reputation report.

Step 4 — Review Your Reputation Score

The headline reputation score gives you an immediate overall picture of your blacklist standing. A high score means you are clean. A low score indicates listings that need to be addressed.

Step 5 — Review the Detailed Results Table

The per-blacklist results table shows the specific status for each database checked — whether your domain or IP is listed or clean on each one individually. Focus first on any listings on the major databases — Spamhaus, SpamCop, SURBL, and Barracuda — as these have the widest impact on email deliverability.

Step 6 — Read the Recommendations

The recommendations section provides specific, actionable steps for each blacklist where a listing was found — including the delisting process for that specific database and what underlying issues need to be resolved first.

Step 7 — Export or Copy Your Report

Use Export Report to download your complete blacklist scan report, or Copy Summary to copy key findings to your clipboard for sharing with your hosting provider, email administrator, or developer.

How to Get Delisted From Blacklists

Getting removed from a blacklist requires two things in the correct order: first fix the underlying problem that caused the listing, then submit a delisting request. Submitting a delisting request without fixing the root cause will result in re-listing, often faster than the first time.

Step 1 — Identify and Fix the Root Cause

Before contacting any blacklist for delisting, you must resolve the underlying issue:

If your server was compromised:

• Change all passwords immediately — hosting, email, CMS, FTP, database
• Update all software — WordPress core, plugins, themes, and server software
• Scan for and remove malware using a server-side scanner
• Review server logs to identify how the compromise occurred and close that vulnerability
• Consider engaging a professional security firm if the compromise was severe

If you sent bulk email that generated complaints:

• Immediately stop the campaign that generated complaints
• Review your list for proper opt-in compliance
• Add or fix your unsubscribe mechanism
• Implement proper email authentication (SPF, DKIM, DMARC)
• Reduce sending volume and improve content quality before resuming

If the issue was inherited from a previous owner:

• Document that you are the new owner of the domain or IP
• Demonstrate that the previous abusive activity has ceased
• Show evidence of legitimate use (website content, business registration, etc.)

Step 2 — Submit Delisting Requests

Each blacklist has its own delisting process. Here is how to approach the major ones:

Spamhaus Delisting: Spamhaus provides a lookup tool at their website (check.spamhaus.org) that shows the specific reason for listing and the delisting procedure for each of their lists. The SBL and XBL require resolving the underlying issue and submitting a delisting request through the Spamhaus website. The PBL can often be managed by ISPs on behalf of their customers.

SpamCop Delisting: SpamCop listings expire automatically once the volume of incoming spam complaints from your IP drops below the threshold — typically within 24 to 48 hours of the spam source stopping. The most effective approach is to stop the spam activity and wait. There is no manual delisting option for SpamCop.

SURBL Delisting: SURBL provides a removal request process through their website. You need to document why your domain should not be listed — for example, that your site was compromised and has since been cleaned.

Barracuda Delisting: Barracuda provides a public delisting request form at their website (barracudacentral.org/rbl/removal-request). Submit your IP address and a brief explanation of why you believe it was incorrectly listed or why the issue has been resolved.

For smaller blacklists: Each smaller blacklist has its own delisting process — usually accessible through their website. Some delist automatically after a cooling-off period. Others require a manual request. The recommendations section in your report provides specific guidance for each blacklist where a listing is found.

Step 3 — Verify Delisting

After submitting delisting requests and allowing sufficient time for processing (typically 24 to 72 hours), run another blacklist check using this tool to verify that the listings have been removed. Some blacklists update their public databases within minutes of approving a delisting request; others may take longer.

The Impact of Blacklisting on Email Deliverability

Email deliverability is the measure of how successfully your emails reach recipients’ inboxes rather than being blocked or filtered to spam. Blacklisting is one of the most severe deliverability problems because it operates at the infrastructure level — before spam filters even evaluate your email content.

Here is how blacklisting affects email at each stage:

Immediate rejection (bounce) Some receiving mail servers are configured to immediately reject email from blacklisted IPs with a 550-series SMTP error code. The email never reaches the recipient’s mailbox — not even their spam folder. The sender receives a bounce notification indicating delivery failure.

Spam folder filtering Many systems use blacklists as one factor in a weighted spam scoring system. A blacklisted IP increases the spam score enough to push legitimate emails into spam folders rather than outright rejecting them.

Reduced sender reputation with major providers Gmail, Outlook, and Yahoo mail all maintain their own internal sender reputation systems. Repeated blacklist listings — even after delisting — can negatively influence your long-term sender reputation with these providers, affecting deliverability for months after the listings are removed.

Impact on transactional email Blacklisting does not distinguish between marketing email and critical transactional email — order confirmations, password resets, account activations, shipping notifications. All email from a blacklisted source is affected equally, which can have direct business impact beyond just marketing.

Preventing Future Blacklist Listings

Once you are delisted, these practices help keep your domain and IP clean:

Implement proper email authentication Set up SPF, DKIM, and DMARC records for your domain. These standards authenticate your email, reduce the chance of your domain being spoofed in spam campaigns, and improve your sender reputation with major email providers.

Use a dedicated sending IP for bulk email If you send marketing email in volume, use a dedicated IP address or a reputable email service provider (ESP) like Mailchimp, Sendgrid, or Campaign Monitor. These services maintain strong sending reputations and handle deliverability management on your behalf.

Monitor your server for compromise indicators Set up log monitoring for unusual outbound email activity. Automated alerts for unexpected email volume spikes can catch a compromise early — before a blacklisting occurs.

Keep all software updated The majority of server compromises that lead to blacklisting result from exploited vulnerabilities in outdated software. Keeping WordPress, plugins, server software, and control panel software up to date eliminates the most common attack vectors.

Practice proper list hygiene Remove bounced addresses after the first hard bounce. Remove unsubscribers immediately. Never add email addresses to your list without explicit opt-in confirmation. Regularly clean your list to remove long-inactive subscribers.

Monitor your blacklist status regularly Run periodic blacklist checks — monthly at minimum, weekly if you send high volumes of email — so that any new listing is detected and addressed quickly before it significantly impacts your deliverability.

Who Should Use This Blacklist Lookup Tool?

Email Marketers and Newsletter Senders Before every major campaign, run a blacklist check on your sending IP and sending domain. A listing discovered before a campaign allows you to resolve it before it affects delivery. A listing discovered after the campaign explains low open rates and prevents you from sending to the same list again until resolved.

Business Owners and Website Managers If your customers are not receiving your transactional emails — order confirmations, invoices, password resets — a blacklisting may be the cause. A quick check often reveals the problem faster than a support ticket to your hosting provider.

IT Administrators and Email Administrators Blacklist monitoring is standard practice for any organization that manages its own mail servers. Use this tool for quick spot checks and incorporate regular automated blacklist monitoring into your email infrastructure maintenance routine.

Web Developers and Hosting Teams After launching a new website or setting up a new server, verify that the assigned IP address is clean before pointing your client’s domain to it. Inherited blacklist listings from a previous server occupant are a common and avoidable problem.

Domain Investors and Buyers Before purchasing any domain, check its blacklist status. A domain previously used for spam campaigns may carry an inherited reputation problem that takes months to clean up — significantly affecting its value and usability.

SEO Professionals and Digital Marketers A blacklisted domain can be blocked by browser safe browsing systems, reducing organic traffic from users who receive security warnings when trying to visit the site. Include blacklist checks in technical SEO audits, particularly for clients who have recently experienced unexplained traffic drops.

Security Professionals Blacklist status is a quick, valuable data point in any security assessment or threat investigation. A domain or IP found on multiple security-focused blacklists is a strong indicator of current or recent malicious activity.

Frequently Asked Questions

Q: Is this blacklist lookup completely free? Yes — 100% free with no account required, no subscription, and no usage limits. Check as many domains and IP addresses as you need.

Q: Can I check both a domain and an IP address? Yes. The tool has separate tabs for checking domain names and IP addresses. Both are equally important — your domain may be listed on domain-focused blacklists while your mail server IP is listed on IP-focused blacklists, or vice versa.

Q: How did my domain or IP get blacklisted? The most common causes are: a server being hacked and used to send spam, bulk email generating excessive complaints, a phishing or malware association, inheriting a previous owner’s bad reputation, or an open mail relay being exploited. The recommendations section provides specific guidance based on which blacklists flagged your domain or IP.

Q: How long does delisting take? It varies by blacklist. SpamCop listings expire automatically in 24 to 48 hours once the spam activity stops. Spamhaus manual delisting requests are typically reviewed within 24 hours after the underlying issue is resolved. Barracuda typically responds within 24 to 48 hours. Smaller blacklists vary widely — some update within minutes, others within days.

Q: Will fixing the issue automatically get me delisted? Not always — it depends on the blacklist. SpamCop delists automatically when complaint volume drops. Most other blacklists require you to submit a manual delisting request after fixing the underlying issue. Simply fixing the problem without requesting delisting may leave you listed indefinitely on some databases.

Q: My emails are going to spam — is blacklisting definitely the cause? Not necessarily. Spam filtering is complex and involves many factors beyond blacklisting — email content, sender reputation with individual providers, SPF/DKIM/DMARC authentication status, recipient engagement history, and more. Run a blacklist check as your first diagnostic step. If no listings are found, the problem likely lies elsewhere — in your authentication configuration, content, or sender reputation with specific providers.

Q: Can I be blacklisted even if I did not send spam? Yes. Blacklisting can occur through no fault of your own — for example, if your server was hacked without your knowledge, if a previous owner of your domain or IP had a poor reputation, if spammers spoofed your domain in their campaigns, or if your website was compromised and used in phishing attacks.

Q: Does being blacklisted affect my Google rankings? Indirectly, yes. If your website is listed on security-focused blacklists (like Google’s own Safe Browsing list), browsers may display security warnings that prevent visitors from accessing your site — dramatically reducing traffic. Additionally, a blacklisted domain that cannot deliver email loses customer communication capabilities, which affects business operations that support your online presence.

Q: How often should I check my blacklist status? Monthly monitoring is the minimum recommended frequency. Weekly checks are better for organizations that send high volumes of email. Immediately after any server incident, security event, or unexplained drop in email deliverability — always run a blacklist check as a first diagnostic step.

Q: What is DNSBL? DNSBL (DNS-Based Blackhole List) is the technical standard for how most spam blacklists operate. They store listings as DNS records so that mail servers can query them using the same DNS infrastructure already used for all internet lookups. Your mail server can check whether an IP is listed by performing a simple, fast DNS query to the blacklist’s DNS servers — making blacklist lookups extremely efficient at scale.

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