IP Blacklist Checker
Check a public IPv4 address or mail server hostname against common DNS-based email blocklists.
IP Blacklist Checker checks a public IPv4 address or mail server hostname against common DNS-based blocklists, also called DNSBLs or RBLs. These lists are often used by mail systems to help identify addresses associated with spam, open relays, compromised hosts, malware, proxy abuse, or poor sending reputation.
IP Blacklist Checker
Enter the required values and run the tool to view results.
Recommended Next Checks
Continue the same task with related tools. When possible, your current input is carried to the next page.
Data Breach Check
Review email format, mail-domain security records, and trusted options for live breach exp...
Scam Trust Score Checker
Quick check for scams, and report scams with a single click to help protect others.
Password Strength Test
Estimate password strength and review practical ways to make passwords longer, stronger, a...
WP Scanner
Use WP Scanner for a quick, focused task.
What the IP Blacklist Checker Does
The tool resolves a hostname to a public IPv4 address when needed, reverses the address into DNSBL query format, and checks a curated set of DNSBL zones. The result shows whether the address is listed, the blocklist zone checked, DNS response codes, and TXT details when the provider publishes an explanation.
DNSBL results are not the same as a complete email deliverability audit. A mail server can have delivery problems because of missing PTR records, SPF, DKIM, DMARC, HELO/EHLO mismatch, rate limits, compromised accounts, message content, or sender behavior even when no DNSBL listing is found.
How to Use IP Blacklist Checker
Enter a public IPv4 address or a mail server hostname. The tool checks the resolved IPv4 address against multiple DNSBL zones and reports listed and clear results in a table. If a listing appears, review the named blocklist provider directly for policy details and delisting instructions.
Use this report as a starting point for troubleshooting mail delivery and reputation. For production mail systems, also verify reverse DNS, SPF, DKIM, DMARC, TLS, bounce handling, abuse complaints, and sending volume patterns.
Related Tools
Data Breach Check
Review email format, mail-domain security records, and trusted options for live breach exposure checks.
Scam Trust Score Checker
Quick check for scams, and report scams with a single click to help protect others.
Password Strength Test
Estimate password strength and review practical ways to make passwords longer, stronger, and unique.
WP Scanner
Use WP Scanner for a quick, focused task.
WordPress Auth Salt Generator
Generate WordPress authentication salts and security keys.
Strong Password Generator
Generate a strong password with letters, numbers and symbols.
Suggest an improvement
Tell us if something is confusing, broken, incorrect, or missing. Feedback helps us improve the tools and workflows people use every day.