Real-time Blackhole List Scanner
Enter your mail server's IP address to execute reversed lookups against the world's most prominent Real-time Blackhole Lists (RBL).
Real-Time Blackhole List Diagnostics
Ensure your Mail Transfer Agent (MTA) is fully trusted. We execute live, uncached reversed IPv4 lookups against over 50 global Real-time Blackhole Lists (RBLs) simultaneously. Instantly detect open relays, pinpoint spam trap hits, and precisely parse 127.0.0.x return codes to resolve 550 SMTP rejection errors in real-time.
Enter your mail server's IP address to execute reversed lookups against the world's most prominent Real-time Blackhole Lists (RBL).
If your Mail Transfer Agent (MTA) is listed on a Real-time Blackhole List, major inbox providers will drop your connections instantly. Run an RBL check to verify your network integrity.
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