Blacklist Checker
Enter a domain or IPv4 address to check it against several major spam and reputation blacklists.
Overview
DNSBLs (DNS-based Blacklists, also called RBLs — Realtime Blackhole Lists) are third-party lists mail servers and security tools consult to decide whether to trust traffic from an IP or domain. Getting listed on one can cause outgoing email to be rejected or marked as spam, so checking status here is a useful first step when diagnosing deliverability problems.
This tool queries a curated set of well-known, widely-used blacklist providers over DNS. A domain is checked both against a domain-reputation list and, via its resolved IP address(es), against IP-reputation lists — an IPv4 address is checked directly against the IP lists.
Coverage is IPv4-only, since the DNSBL/RBL ecosystem is still overwhelmingly IPv4-based and most providers don't index IPv6 space.
Examples
Checking an IPv4 address
8.8.8.8
Spamhaus ZEN: not listed
How It Works
- Enter a domain name or IPv4 address.
- Complete the verification check if shown.
- Click Check to query each blacklist provider.
- Review which providers, if any, list the target.
Use Cases
Diagnosing email deliverability problems
Check whether your mail server's IP has landed on a spam blacklist before troubleshooting further.
Vetting a new IP or domain
Check an IP address or domain's reputation before putting it into production, e.g. after acquiring a new server.
Tips
- A listing on one provider doesn't necessarily mean others list it too — reputation providers use different data sources and criteria.
- If you're listed, most providers publish their own delisting/removal process — this tool only reports status, it can't request removal on your behalf.
FAQ
The domain or IP you enter is sent to our server, which queries each blacklist provider over DNS on your behalf — nothing else about you is sent or stored.
This check queries several external blacklist providers on your behalf, so a quick bot check helps keep the tool available and responsive for everyone.
Most DNSBL/RBL providers only index IPv4 address space, so an IPv6 lookup wouldn't return a meaningful result from most of them.
No — it checks a curated set of well-known, widely-used providers, not every DNSBL that exists. This is meant as a useful first signal, not an exhaustive reputation audit.