IP Blacklist Checker
Check whether an IP address is listed on major DNS-based spam blacklists (DNSBLs).
About the IP Blacklist Checker
Mail servers use DNS-based blacklists (DNSBLs) to decide whether to accept email from a given IP. If your sending IP gets listed, your messages can land in spam — or be rejected outright.
This tool queries several well-known DNSBLs in real time and tells you exactly where an IP is listed, so you can request delisting and protect your email deliverability.
Frequently asked questions
Common causes include a compromised server sending spam, a misconfigured mail server, a shared IP with a bad neighbour, or being part of a previously abused range.
Each DNSBL has its own delisting process on its website. First fix the root cause (secure the server, fix SPF/DKIM/DMARC), then submit a delisting request.
No — blacklists are only one signal. Authentication (SPF, DKIM, DMARC), sending reputation and content all affect deliverability.
Spamhaus ZEN & DBL, SpamCop, Barracuda, SORBS and UCEPROTECT-1 — among the most widely used by mail providers.