What is an IP Blacklist?

An IP blacklist, also known as a Real-time Blackhole List (RBL) or DNSBL, is a database of IP addresses known for sending spam, hosting malware, or engaging in other abusive activities. Being listed can prevent email delivery or block access to services.

Why Check Blacklist Status?

• Ensure your emails reach inboxes and avoid spam filters.
• Maintain a good reputation for your IP.
• Detect if your server has been compromised or misused.
• Prevent downtime or blocks from major providers.

How It Works

This tool queries multiple RBL databases by performing DNS lookups. If the lookup returns a specific response (e.g., 127.0.0.x), the IP is listed. We check against the top 30 reliable lists including Spamhaus Zen, Barracuda, SpamCop, and more (updated for 2026).