What is an IP blacklist (DNSBL)?
DNS-based blackhole lists are databases of IP addresses that have sent spam, hosted malware or shown other abusive behaviour. Mail servers query them in real time and reject or flag email from listed addresses.
If your mail server's IP is listed, your messages may bounce or land in spam folders. Shared hosting and cloud IPs are frequently listed because a previous user abused them.
How to get delisted
First fix the cause: secure compromised accounts, close open relays, and make sure your server has valid reverse DNS (PTR), SPF, DKIM and DMARC records. Then follow the removal procedure on the blacklist's website — most lists offer a self-service form and some expire entries automatically after a period without new spam.
Perguntas frequentes
Why does Spamhaus show an error?
Spamhaus refuses queries that arrive through large public DNS resolvers. An error means the result is unavailable, not that the IP is listed.
Can I get alerts when my IP is listed?
Yes. Paid plans include blacklist monitors that check your IPs every 6 hours and email you when the status changes.