Check if an IP address appears on major DNS-based email blacklists (DNSBLs). Essential for email deliverability and spam investigation.
IP Blacklist Checker
An IP blacklist (also called a DNSBL or RBL — DNS Blackhole List / Realtime Blackhole List) is a database of IP addresses associated with spam, malware, phishing, or other malicious activity. Mail servers query these lists in real-time to decide whether to accept or reject incoming connections.
Email Blacklists
Spamhaus, Barracuda, and Sorbs maintain widely-used email blacklists. Being listed here means your mail server's emails will be rejected or sent to spam by most major providers.
Web Blacklists
Google Safe Browsing, Surbl, and URIBL flag IPs and domains associated with phishing pages, malware distribution, and drive-by download attacks.
How to Delist
Most blacklists offer a self-service removal form. Fix the underlying issue first (secure the server, stop spam), then submit a removal request with justification.
Check Frequency
Monitor your mail server IP weekly. New listings can appear within hours of a compromised account or misconfigured relay sending spam.
Frequently Asked Questions
Why is my IP blacklisted?
Common reasons include: an email account on the server was compromised and used for spam, the server is an open relay, the IP was previously used by a spammer, or your IP range was listed due to a neighbouring IP on a shared hosting block.
How long does delisting take?
Automated delisting usually takes 24–48 hours after the request is approved. Some manual-review lists like Spamhaus may take longer and require detailed remediation evidence.