Blacklist Email Checker

Enter your domain to look up its MX (mail exchange) records and get direct links to check each mail server IP against major email blacklists. Blacklisted IPs are one of the most common causes of email delivery failures.

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What Are Email Blacklists?

Email blacklists (also called DNSBLs — DNS-based Blackhole Lists) are databases of IP addresses and domains known to send spam or malicious email. Mail servers query these lists in real-time during the SMTP transaction. If your sending IP appears on a blacklist, receiving servers may reject your email outright or route it to the spam folder.

Blacklists work through DNS — the same system that resolves domain names to IP addresses. When a mail server receives a connection, it performs a reverse lookup of the sending IP against one or more blacklist databases. This happens transparently before your email even reaches content filtering. You can check how DNS works with our DNS Lookup tool.

Major Email Blacklists

There are dozens of blacklists, but these are the most influential ones that mail servers commonly check:

Blacklist	Operator	Impact Level	Listing Criteria
Spamhaus SBL	Spamhaus	Very High	Verified spam sources, known spammers
Spamhaus XBL	Spamhaus	Very High	Exploited systems, botnets, proxies
Spamhaus PBL	Spamhaus	High	Dynamic/residential IPs (shouldn't send email directly)
Barracuda BRBL	Barracuda Networks	High	IP addresses sending spam to Barracuda traps
SpamCop BL	Cisco/SpamCop	Medium	User-reported spam with automated verification
SORBS	Proofpoint	Medium	Open relays, spam sources, dynamic IPs
UCEPROTECT	UCEPROTECT	Low-Medium	Three levels: IP, /24 block, ASN
Invaluement	Invaluement	Medium	Snowshoe spam detection

Pro Tip: Spamhaus is by far the most widely used blacklist. Being listed on Spamhaus SBL or XBL will cause delivery failures at the majority of mail servers worldwide. If you find yourself listed, prioritize Spamhaus delisting first. Always check your IP with our IP Blacklist Checker and IP Lookup tools to understand your reputation status.

How to Check If You're Blacklisted

Follow this process to determine if your email server is on any blacklists:

Find your mail server IP — Use the tool above to look up your domain's MX records and resolve them to IP addresses.
Check major blacklists — Query each blacklist using the provided links or use our IP Blacklist Checker for a comprehensive scan.
Check your domain too — Some blacklists (like Spamhaus DBL and SURBL) list domains, not just IPs.
Verify PTR record — Use our Reverse DNS Lookup to confirm your IP has a valid PTR record.

Why IPs Get Blacklisted

Understanding the root causes helps prevent future listings:

Cause	Description	Prevention
Compromised server	Hacker sends spam through your server	Update firmware, use strong passwords
Open relay	Mail server accepts email from anyone	Configure authentication requirements
Spam traps	Sending to recycled or pristine trap addresses	Clean email lists regularly
High complaint rate	Recipients marking your email as spam	Implement proper unsubscribe, send wanted content
Shared IP	Other sender on same IP sends spam	Use dedicated sending IP for important email
Infected device	Malware on your network sends spam	Secure your network, scan for malware

Note: If you're on a residential internet connection, your IP is likely already on Spamhaus PBL by default. This isn't because you've sent spam — it's because residential/dynamic IPs aren't intended for direct email sending. You should use your ISP's SMTP server or a third-party email service instead of sending directly. Check your IP type with our What Is My IP tool.

How to Get Delisted from a Blacklist

Each blacklist has its own delisting process. Here's the general approach:

Identify and fix the cause — Don't request delisting until you've stopped the spam. Check your server logs, secure compromised accounts, and clean your email lists.
Submit a delisting request — Visit the blacklist's website and follow their removal process. Most require you to identify yourself and explain what caused the listing and what you've done to fix it.
Wait for removal — Some blacklists (like SpamCop) automatically expire after 24-48 hours if no new spam is detected. Others (like Spamhaus) require manual review.
Monitor after delisting — Set up regular monitoring to catch any re-listing quickly. Check your IP reputation weekly.

Preventing Blacklisting

The best approach is preventing blacklisting in the first place. Implement these measures to protect your email reputation:

Configure SPF, DKIM, and DMARC — Authenticate all your email with proper DNS records. Verify with our DNS Lookup.
Secure your network — Secure your WiFi, update router firmware, and use strong passwords.
Use a dedicated sending IP — Don't share sending IPs with untrusted parties.
Monitor your open ports — Ensure only necessary ports are exposed to the internet.
Set up proper port forwarding — Don't expose your mail server unnecessarily.
Implement rate limiting — Prevent compromised accounts from sending large volumes of spam.

Key Takeaways

Email blacklists (DNSBLs) are DNS-based databases that receiving servers check in real-time during email delivery.
Spamhaus is the most impactful blacklist — being listed there affects delivery to the majority of mail servers.
Common causes of blacklisting include compromised servers, open relays, spam trap hits, and high complaint rates.
Always fix the root cause before requesting delisting — otherwise you'll be re-listed quickly.
Residential IPs are on Spamhaus PBL by default — use your ISP's SMTP server or a dedicated email service.
Prevent blacklisting with proper authentication (SPF/DKIM/DMARC), network security, and email list hygiene.

Video: Understanding Email Blacklists

Related Tools and Guides

Frequently Asked Questions

How do I know if my email server is blacklisted?

Enter your domain in the tool above to find your mail server's IP addresses, then check each IP against major blacklists like Spamhaus, Barracuda, and SpamCop. You can also use our IP Blacklist Checker for a comprehensive scan across multiple blacklists simultaneously.

How long does it take to get removed from a blacklist?

Removal timeframes vary by blacklist. SpamCop automatically delists IPs within 24-48 hours if no new spam is detected. Spamhaus SBL typically processes manual removal requests within 24 hours. Barracuda BRBL can take up to 12 hours. Some blacklists like UCEPROTECT have fixed expiry periods that cannot be expedited.

Can I send email from a residential IP?

Technically yes, but it's not recommended. Most residential IPs are listed on Spamhaus PBL and other policy-based blacklists by default. This means many mail servers will reject your direct email. Use your ISP's SMTP server (usually on port 587) or a professional email service provider instead.

What is the difference between IP and domain blacklists?

IP-based blacklists (like Spamhaus SBL/XBL) list the sending server's IP address. Domain-based blacklists (like Spamhaus DBL and SURBL) list the domains found in email content or the sender's domain. Both types can cause delivery failures, but IP blacklists are more commonly checked during the SMTP connection.

Does being on one blacklist mean I'm on all of them?

No. Each blacklist operates independently with its own listing criteria. You might be listed on SpamCop but not Spamhaus, or vice versa. However, being listed on any major blacklist indicates a problem that could lead to listings on others if not addressed promptly.

Can a shared hosting IP affect my email?

Yes. If you share a sending IP with other users (common with shared hosting), another user's spam can cause the IP to be blacklisted, affecting everyone on that IP. This is a strong reason to use a dedicated sending IP for business email or to use a dedicated email service provider.

About Tommy N.

Tommy is the founder of RouterHax and a network engineer with 10+ years of experience in home and enterprise networking. He specializes in router configuration, WiFi optimization, and network security. When not writing guides, he's testing the latest mesh WiFi systems and helping readers troubleshoot their home networks.