Check if an IP address or domain is listed on DNS-based blacklists (DNSBL/RBL). Scan across multiple blacklist providers simultaneously. Free, no sign-up required.
DNSBL Blacklist Check – IP Reputation Lookup
What Are DNS Blacklists (DNSBL)?
DNS-based Blackhole Lists (DNSBLs), also known as Real-time Blackhole Lists (RBLs), are databases of IP addresses associated with spam, malware, or other malicious activity. Mail servers and security systems query these lists in real-time to decide whether to accept, reject, or flag incoming connections.
Being listed on a DNSBL can severely impact your email deliverability and server reputation. Our tool checks your IP address against all major blacklist providers simultaneously, giving you a comprehensive overview of your IP reputation.
Email Blacklists
Email-focused DNSBLs like Spamhaus SBL, Barracuda, and SpamCop track IP addresses known to send spam or phishing emails. Being listed here directly impacts your email deliverability across major providers.
Security Blacklists
Security-focused lists like Spamhaus XBL, DroneBL, and Abuse.ch track IP addresses involved in malware distribution, botnet activity, or exploitation attempts. These lists protect networks from known threats.
Policy Blacklists
Policy-based lists like the Spamhaus PBL and UCEPROTECT policy lists flag IP ranges that should not be sending email directly, such as residential IP addresses or dynamic IP pools. These are not indicators of abuse but of policy violations.
How the DNSBL Check Works
1. Enter an IP address – Type any IPv4 address to begin the blacklist scan.
2. Reverse DNS lookup – The IP address is reversed and queried against each blacklist’s DNS zone (e.g., 4.3.2.1.zen.spamhaus.org).
3. Parallel scanning – All blacklist queries run simultaneously for fast results across dozens of providers.
4. Result interpretation – A positive DNS response means the IP is listed. We decode the return codes to show the specific listing reason.
5. Delisting guidance – For each listing found, we provide information about the blacklist and guidance on how to request removal.
How to Get Delisted from a DNSBL
Identify the root cause – Before requesting removal, determine why your IP was listed. Common causes include compromised accounts sending spam, misconfigured mail servers, or malware infections.
Fix the underlying issue – Remove malware, secure compromised accounts, update software, and implement proper email authentication (SPF, DKIM, DMARC). Blacklists will relist you if the problem persists.
Request removal – Most blacklists offer a self-service delisting process. Visit the blacklist’s website and follow their removal procedure. Some lists automatically delist after a period of no further incidents.
Monitor regularly – After delisting, continue to monitor your IP reputation. Use this tool periodically to ensure you remain clean across all major blacklists.
Prevention tips:
• Implement rate limiting on your mail server
• Use strong passwords and enable 2FA for all email accounts
• Keep your server software and CMS up to date
• Monitor outbound email traffic for anomalies
• Set up reverse DNS (PTR record) for your mail server IP
Frequently Asked Questions
What does it mean if my IP is blacklisted?
It means your IP address has been flagged for suspicious activity such as sending spam, distributing malware, or being part of a botnet. This can affect your ability to send emails and may indicate a security compromise.
How often should I check my IP reputation?
For mail servers, check weekly or after any security incident. For web servers, check monthly. Set up automated monitoring if you manage critical infrastructure.
Can I be listed even if I haven’t done anything wrong?
Yes. If your IP was previously used by someone who engaged in abuse, the listing may carry over. Shared hosting environments can also cause innocent users to be listed due to a neighbor’s bad behavior.
How long does delisting take?
It varies by provider. Some blacklists process removal requests within hours, while others may take several days. A few lists automatically delist after a quiet period (typically 1-4 weeks).
What is the difference between DNSBL, RBL, and blacklist?
These terms are often used interchangeably. DNSBL (DNS-based Blackhole List) is the technical name for the protocol. RBL (Real-time Blackhole List) was the original term coined by MAPS. “Blacklist” is the common informal term for all such lists.