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🚫 23 DNSBLs · Real Lookups · IP & Domain · Live Results

Email Blacklist Checker

Free email blacklist checker — check any domain or IP address against 23 major spam blacklists including Spamhaus, Barracuda, SpamCop, SORBS, URIBL, and SURBL using real DNSBL lookups. No signup required.

✓ 23 blacklists✓ IP & domain support✓ Real DNSBL protocol✓ DNS over HTTPS✓ No signup
Check IP or Domain Against 23 Blacklists
Checks via real DNSBL lookups using encrypted DNS over HTTPS (Cloudflare DoH, Google DoH fallback). Email addresses are automatically stripped to the domain. No data is stored or logged.
What this tool does

Free email blacklist checker — check IP and domain reputation against 23 DNSBLs

This email blacklist checker performs real DNSBL (DNS-based Blackhole List) lookups against 23 major spam and reputation databases. Enter any IP address, domain name, or email address — the tool automatically strips email addresses to just the domain, resolves the domain to its IP when needed, and queries each applicable blacklist using the authentic DNSBL protocol over encrypted DNS over HTTPS (Cloudflare primary, Google fallback).

A single blacklisting on Spamhaus ZEN or Barracuda BRBL can cause a significant portion of your email to be rejected or routed to spam by Gmail, Outlook, Yahoo, and enterprise mail gateways worldwide. Domain-based lists like Spamhaus DBL, URIBL, and SURBL affect email where your domain appears as a link or sender address — even when using a reputable third-party email provider. This tool checks both IP and domain blacklists so you get a complete picture of your sending reputation.

If a listing is found, the return code is displayed — this often encodes the reason for listing (spam source, botnet, policy block, etc.). Use this information to diagnose the root cause before submitting a delisting request to the relevant blacklist operator.

Major blacklists checked
Spamhaus ZENSpam/IP
Combines SBL, XBL, and PBL — the most widely adopted IP blacklist. A listing here causes rejection at most major mail providers.
Spamhaus DBLDomain
Domain Block List — lists domains found in spam. Affects links in email body, From: and Reply-To: addresses.
Barracuda BRBLSpam/IP
Used by Barracuda spam filters deployed across enterprises worldwide. Self-service delisting available.
SpamCop BLSpam/IP
Based on spam reports submitted by users. Listings expire automatically after spam activity stops.
URIBL MultiDomain
URI-based domain list. Blocks domains appearing as links in spam messages regardless of sending IP.
SURBL MultiPhishing
Focuses on domains used in phishing and malware campaigns. Widely used by enterprise spam filters.
Abuseat CBLBotnet
Tracks IPs sending spam via botnets, worms, or malware. Included within Spamhaus XBL.
SORBS DNSBLSpam/IP
Spam and Open Relay Blocking System — one of the oldest blacklists, covering multiple abuse categories.
Examples

What blacklist results look like -- listing types and their impact

These examples show how different blacklist results appear and what each means for email deliverability.

Listed -- CriticalSpamhaus ZEN -- highest impact, hard reject at most servers
IP: 203.0.113.45 Blacklist: Spamhaus ZEN (SBL+XBL+PBL combined) Return: 127.0.0.2 (SBL -- direct spam source) Impact: Very High -- hard rejected by most major mail servers

A Spamhaus ZEN listing is the most damaging blacklist appearance for email deliverability. The ZEN zone combines three Spamhaus lists into one query. Return code 127.0.0.2 indicates a direct spam source listing. Most enterprise mail servers and ISPs hard-reject all email from listed IPs without delivering it at all.

Listed -- HighBarracuda BRBL -- 200,000+ organisations block this IP
IP: 198.51.100.22 Blacklist: Barracuda Reputation Block List (BRBL) Return: 127.0.0.2 Impact: High -- Barracuda appliances deployed at 200,000+ organisations

Barracuda's BRBL is queried by its email security appliances at over 200,000 organisations worldwide. A listing here means email from this IP is blocked or heavily filtered by any organisation using Barracuda gateway products. Delisting requires a request via Barracuda's reputation lookup portal.

Listed -- MediumSORBS DUHL -- residential IP, not authorised for direct delivery
IP: 192.0.2.100 Blacklist: SORBS DUHL (Dynamic User and Host List) Return: 127.0.0.10 Impact: Medium -- expected fix is to use a proper SMTP relay

SORBS DUHL lists consumer and dynamic IP ranges that should not send email directly to mail servers. This does not mean your IP sent spam -- it means it is in a residential range. Fix: route all outbound email through your ISP's SMTP relay or a dedicated sending service rather than direct-to-MX connections.

CleanIP not listed on any checked blacklist
IP: 198.51.100.50 Blacklists: 10+ checked (Spamhaus, Barracuda, SURBL, others) Result: No listings found Status: Clean across all sources

A clean result across all checked blacklists is the expected state for a healthy sending IP. Maintain clean status by keeping spam complaint rates below 0.1%, authenticating with SPF, DKIM, and DMARC, and monitoring deliverability metrics regularly. New listings can appear without warning so check monthly.

Listed -- ContentURIBL -- domain found in spam URLs, not a network listing
Domain: example-spam.com Blacklist: URIBL (URI Reputation Block List) Return: 127.0.0.2 Impact: Moderate -- affects emails containing this domain as a link

URIBL lists domains that appear in spam message bodies rather than sending IP addresses. A URIBL listing means the domain is associated with spam content and affects deliverability when the domain appears as a link inside email body text, regardless of which server sent the message.

FAQ

Frequently asked questions about email blacklist checking

What is an email blacklist?
An email blacklist (also called a DNSBL — DNS-based Blackhole List, or RBL — Real-time Blackhole List) is a database maintained by anti-spam organizations that tracks IP addresses and domains known to send spam, host malware, or engage in phishing. Receiving mail servers query these lists in real time to decide whether to accept, filter, or reject incoming email. A listing on even one major blacklist like Spamhaus ZEN can cause a significant portion of email from that IP to be rejected or sent to spam.
How does a DNSBL lookup work?
The lookup mechanism uses the DNS system. To check if IP 1.2.3.4 is listed on zen.spamhaus.org, a DNS query is made for the A record of 4.3.2.1.zen.spamhaus.org (the IP reversed and appended to the zone). If an A record is returned, the IP is listed — the return code (such as 127.0.0.2) often encodes the reason. An NXDOMAIN response means the IP is clean. Domain-based lists (like DBL, URIBL) work similarly but use the domain name directly.
What should I do if my IP or domain is blacklisted?
First, identify and fix the root cause — this could be compromised email accounts sending spam, a malware infection, a linked domain appearing in spam campaigns, or a sudden spike in sending volume that triggered automated listing. Once the underlying issue is resolved, visit each blacklist's website directly to submit a delisting request. Most major lists like Spamhaus offer automated removal tools. After delisting, monitor your sending reputation closely.
How long does blacklist removal take?
It varies by list. Spamhaus typically processes removal requests within 24 hours if the spam source is genuinely resolved. Barracuda BRBL offers automated delisting that can take effect within hours. Some smaller lists auto-expire entries after a set period if no new spam is detected from the IP. During the removal period, consider using a different IP or a reputable email service provider to maintain deliverability.
Which blacklists matter most for email deliverability?
Spamhaus ZEN (for IPs) and Spamhaus DBL (for domains) have the broadest adoption among major mail providers and affect the most email traffic. Barracuda BRBL and SpamCop BL also significantly impact deliverability with Gmail, Outlook, Yahoo, and enterprise mail servers. URIBL and SURBL can cause domain links within your email body to trigger spam filters even when your sending IP is clean.
Can my domain be blacklisted even if my sending IP is clean?
Yes — domain-based lists like Spamhaus DBL, URIBL, and SURBL list domain names that appear as links inside spam messages, regardless of the IP the spam was sent from. This can affect your domain even if you use a reputable email service provider like SendGrid or Mailgun. If your domain appears in phishing or spam campaigns (which you may not have authorized), it can end up on domain blacklists.
What is the difference between IP blacklists and domain blacklists?
IP blacklists (like Spamhaus ZEN, Barracuda BRBL, SpamCop) list the IP addresses of mail servers that have sent spam or are associated with abuse. Mail servers check the connecting IP at the SMTP connection level. Domain blacklists (like Spamhaus DBL, URIBL, SURBL) list domain names found in spam message content — URLs, From addresses, Reply-To addresses. Both types can independently block or filter email.
How often should I check my blacklist status?
If you're experiencing email deliverability issues (bounces, low open rates, or recipients reporting spam), check immediately. For proactive monitoring, weekly or monthly checks are recommended for high-volume senders. Transactional senders (e-commerce, SaaS) should monitor more frequently since a blacklisting can directly impact business-critical emails like receipts and password resets. Monthly blacklist checks are a minimum best practice -- weekly checks are recommended for high-volume senders or any IP used for transactional email.
Why might my lookup return 'could not resolve IP' for a domain?
This means the domain has no A record — it doesn't resolve to an IP address. This can happen for parked domains, domains configured for receiving email only (no web server), or domains with DNS misconfiguration. For domain blacklist checking (DBL, URIBL, SURBL), the lookup still proceeds using the domain name directly. For IP-based blacklists, we need a resolved IP, so those checks will be skipped.
What do the return codes mean on blacklist results?
When a DNSBL returns an A record indicating a listing, the IP address in the response encodes additional information. For Spamhaus ZEN, 127.0.0.2 means SBL listing (spam source), 127.0.0.4 means XBL listing (exploited system/botnet), and 127.0.0.10/127.0.0.11 mean PBL listing (policy block list — dynamic IP). Return codes vary by blacklist operator, so check the specific list's documentation for the full meaning.
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