What is a DNSBL and why should I check it?
A DNSBL (DNS-Based Blackhole List) is a real-time database that mail servers query to decide whether to accept incoming email. If your domain or sending IP appears on a DNSBL like Spamhaus, Barracuda, or SORBS, receiving servers may silently reject or junk your messages.
What should I do if my domain is on a blacklist?
First, identify the root cause — common triggers are compromised accounts sending spam, bought lists generating complaints, or open relays. Fix the underlying problem, then visit the specific blacklist's website and follow their delisting request process. Most lists delist within 24-48 hours once the issue is resolved.
How many blacklists does this tool check?
This tool scans over 50 of the most widely referenced DNSBL zones in parallel, including Spamhaus ZEN, Barracuda, SORBS, SpamCop, UCEPROTECT, Invaluement, and many more. The scan completes in seconds because it uses asynchronous DNS lookups across all zones simultaneously.
