IP Blacklist Check
Instantly verify your IP addresses against multiple blacklist providers worldwide. Detect blacklisting issues before they impact your email delivery and network reputation.
Why You Should Check Your IP Against Blacklists
IP blacklists (DNSBLs / RBLs) are maintained by anti-spam organizations, security vendors, and email-service providers worldwide. When your IP appears on these lists, outgoing emails may be silently dropped and web traffic may be blocked.
Regular blacklist checks are essential for any organization that sends email, hosts websites, or manages network infrastructure.
This free tool scans your IP address or CIDR range against major blacklist providers and delivers a comprehensive report within seconds. It is especially valuable if you have recently acquired or leased IPv4 address blocks.
- ✔Scans against Spamhaus, Barracuda, SORBS, SpamCop, and many more
- ✔Detects compromised mail servers and open relays
- ✔Identifies inherited reputation issues from previous holders
- ✔Catches false positives triggered by automated detection
- ✔Confirms IPs are clean before network announcement
- ✔Pair with continuous IP Blacklist Monitoring for ongoing protection
Check Your IP Address
Enter an IPv4 address or CIDR range to scan against blacklist databases
Major Blacklist Databases Checked
We query major blacklist providers in real-time, ensuring comprehensive coverage of your IP reputation
Why Check IP Blacklists?
Blacklisted IPs can silently disrupt critical business operations — from email delivery to web hosting
Protect Your Sender Reputation
Blacklisted IP addresses can severely impact email deliverability. A single blacklisted IP in your range can affect your entire subnet and damage your business communications.
Detect Issues Before They Escalate
Proactive blacklist checks help you identify compromised IPs early, preventing widespread delivery failures and potential revenue loss from undelivered transactional emails.
Ensure Clean IP Space for Transactions
Before buying or leasing IPv4 addresses, verify they are not blacklisted. A clean IP reputation is essential for any network operation, from hosting to email services.
Maintain Network Integrity
Regular blacklist checks are part of responsible IP management. ISPs and hosting providers rely on clean IP space to maintain service quality for their customers.
How It Works
Three simple steps to a complete IP blacklist report
Enter Your IP or Subnet
Input a single IPv4 address or a CIDR range (e.g., 192.168.1.0/24) to scan your entire subnet at once.
Scan Multiple Databases
Our Go-powered engine queries blacklist databases in parallel using hundreds of goroutines, delivering results in seconds rather than minutes.
Get Your Report
Receive a detailed interactive report showing each blacklist status, risk assessment, and actionable remediation steps. Download as PDF or share via link.
Frequently Asked Questions
Everything you need to know about IP blacklist checking
An IP blacklist (also called a DNSBL or RBL) is a database of IP addresses that have been flagged for sending spam, hosting malware, or engaging in other abusive network behavior. Email servers and network firewalls reference these lists to block or filter traffic from known-bad sources.
Common reasons include sending spam (even unintentionally), hosting malware or phishing pages, being part of a botnet, having an open relay or proxy, or simply inheriting a previously blacklisted IP address from a prior owner or tenant.
Our IP blacklist check tool scans multiple real-time blacklist databases, including major providers such as Spamhaus, Barracuda, SpamCop, SORBS, and more.
Yes. You can enter a CIDR notation (e.g., 192.168.1.0/24) to scan an entire subnet. We support subnet sizes from /16 to /32, allowing you to check up to 65,536 IP addresses in a single report.
Each blacklist provider has its own delisting process. Generally, you need to identify and fix the root cause (e.g., stop spam, remove malware), then submit a delisting request through the provider's website. Our report includes direct links to delisting pages for each provider where your IP is listed.
For critical infrastructure, we recommend at least weekly checks. For email servers, daily monitoring is ideal. Consider our IP Blacklist Monitoring service for continuous, automated hourly checks with instant alerts when a blacklisting is detected.
Yes, the IP Blacklist Check tool is completely free for individual IP lookups. Subnet scans and bulk checks are available with a free account. For continuous monitoring, check out our IP Blacklist Monitoring plans.