Check if an IP address appears on major DNS-based email blacklists (DNSBLs). Essential for email deliverability and spam investigation.
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.
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.
Google Safe Browsing, Surbl, and URIBL flag IPs and domains associated with phishing pages, malware distribution, and drive-by download attacks.
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.
Monitor your mail server IP weekly. New listings can appear within hours of a compromised account or misconfigured relay sending spam.
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.
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.