Blacklist Checker
Instantly scan your domain or IP against the most widely used DNS-based blacklists. These are the blacklists that have the greatest impact on email deliverability — if you are listed on any of them, your emails will have serious delivery problems.
Accepts domain names (e.g., example.com) or IPv4 addresses (e.g., 192.0.2.1). Domains will be resolved to IP automatically.
What Are Email Blacklists?
Email blacklists (also called blocklists or DNSBLs) are databases of IP addresses and domains that have been flagged for sending spam or malicious email. Mailbox providers like Gmail, Microsoft, and Yahoo use these lists as one factor when deciding whether to accept, filter, or reject incoming email.
Why Blacklist Checking Matters
If your domain or sending IP is on a blacklist, your emails may be silently dropped, sent to spam folders, or rejected entirely. Even a single blacklist listing can have a significant impact on deliverability, depending on which list and which mailbox providers use it.
What We Scan
Our blacklist checker queries the most widely used and impactful DNS-based blacklists — the ones that major mailbox providers like Gmail, Yahoo, Microsoft, and corporate mail systems actively check. A listing on any of these will cause real delivery problems for your email:
- Spamhaus ZEN (SBL, XBL, PBL) - The single most influential blacklist. Used by the vast majority of receiving mail servers worldwide.
- Barracuda BRBL - Widely used by organizations running Barracuda email security appliances and gateways.
- SpamCop - Real-time blacklist driven by user spam reports. Heavily referenced by many providers.
- SORBS - Long-running blacklist covering spam sources, open relays, and open proxies.
- CBL (Composite Blocking List) - Detects compromised hosts and botnet activity. Feeds into Spamhaus XBL.
- UCEPROTECT, Mailspike, DroneBL, PSBL, and more - Additional widely referenced lists that complement the major providers.
What to Do If You Are Listed
- Identify the cause - Common reasons include compromised accounts, open relays, purchased lists, or high spam complaint rates.
- Fix the underlying issue - Clean your mailing list, secure your server, or stop the offending sending practice.
- Request delisting - Most blacklists have a removal process. Visit the blacklist's website for instructions.
- Monitor regularly - Check back periodically to ensure you stay off the lists.
For a complete guide, read our Blacklist Removal Guide.
Frequently Asked Questions
An email blacklist (also called a DNSBL or RBL) is a real-time database of IP addresses and domains that have been identified as sources of spam or malicious email. When you send an email, the recipient's mail server queries these blacklist databases to check whether your sending IP or domain is listed. If a match is found, your email may be rejected or routed to the spam folder. Major blacklists like Spamhaus, Barracuda, and SpamCop are used by most large email providers.
You can check your blacklist status for free by entering your IP address or domain name into our blacklist checker tool, which scans your information against the most widely used DNS-based blacklist databases simultaneously. The results show a clear pass or fail status for each blacklist checked. For the most accurate results, enter the specific IP address your mail server uses to send emails.
If your emails are landing in spam folders, blacklisting is one of the most common causes, but not the only one. Other reasons include missing email authentication records (SPF, DKIM, DMARC), poor sender reputation, spammy content, or sending to outdated email lists. Running a blacklist check is the fastest way to rule out or confirm blacklisting as the cause.
An IP blacklist targets the specific IP address of the mail server sending the email, while a domain blacklist (also called a URIBL) flags the domain name used in email headers or links within the message body. If your IP is blacklisted, all email sent from that server is affected; if your domain is blacklisted, emails are flagged regardless of which IP address is used to send them.
The most common reasons include sending emails to recipients who never opted in, hitting spam traps (fake email addresses placed to catch spammers), receiving a high volume of spam complaints, having a sudden spike in sending volume, or operating a compromised or open-relay mail server. With shared hosting, your IP may be blacklisted due to another user's spamming activity on the same server.
To get delisted, first identify which specific blacklists you are on using our blacklist checker. Fix the underlying issue such as securing your mail server, removing malware, or cleaning your email list. Then visit the blacklist operator's website and submit a delisting request with evidence that the problem has been addressed. Some blacklists like Spamhaus respond within 24-48 hours, while others remove listings automatically after 7-30 days.
Removal timelines vary by blacklist provider. Automated blacklists typically process removal within 24-72 hours once the spam activity stops. Manual blacklists may take one to several weeks as administrators review your request. Major providers like Spamhaus generally respond within 24-48 hours. Even after delisting, your emails may face stricter filtering for several weeks afterward.
There are over 200 known DNS-based email blacklists, but only about 8-10 significantly impact email deliverability. The most important ones include Spamhaus (SBL, XBL, PBL), SpamCop, Barracuda Reputation Block List, SORBS, and Invaluement. Being listed on Spamhaus in particular will cause widespread delivery failures to Gmail, Yahoo, Microsoft, and most corporate mail systems.
Follow these best practices: only send emails to recipients who have explicitly opted in (use double opt-in), regularly clean your email lists to remove invalid addresses, authenticate your emails with SPF, DKIM, and DMARC records, warm up new IP addresses gradually, and keep your spam complaint rate below 0.3%. Monitor your blacklist status at least weekly using a blacklist checker.
If you send emails regularly, you should run a blacklist check at least once a week. Run an immediate check whenever you notice a sudden drop in open rates, an increase in bounce-back messages, or recipient complaints about not receiving your emails. For high-volume senders, daily monitoring or automated alerts are recommended to catch listings early and minimize the impact on deliverability.