Check whether an IP or domain is listed on common DNSBL email blacklists
• Enter a mail server IP or domain (domains resolve to the first IPv4)
• Concurrently queries Spamhaus / SpamCop / Barracuda / SORBS and more
• An 'error' status usually means the blacklist rejects public-resolver queries, not that the IP is clean
An email blacklist check concurrently queries a set of well-known DNSBL (DNS-based Blocklist) services — including Spamhaus, SpamCop, Barracuda, and SORBS — to see whether an IP address or domain appears on any of them. A listing on a major DNSBL is a common reason for outbound email being rejected or delivered to spam.
Common uses include diagnosing email delivery failures caused by a blacklisted sending IP, confirming that a server IP is clean before using it for mail, and checking whether a domain's reputation has been affected after a spam incident or a previous owner's activity.
The IP or domain appears on that specific blacklist, which means receiving servers that use that list may reject or filter mail from it. Each DNSBL has its own listing criteria and removal process.
The DNSBL query returned an error rather than a definitive listed or clean result. Some free DNSBLs reject lookups from public resolvers. An error does not confirm the IP is listed — try again or use the DNSBL's own lookup form.
Each blacklist has its own removal process. Most require you to identify and fix the cause (spam sending, open relay, malware), then submit a delisting request through their website. Spamhaus and SpamCop have well-documented processes.
DNSBL is just one factor. Spam filters also consider domain reputation, content scoring, missing SPF/DKIM/DMARC, sending volume and patterns, and engagement metrics. Check the SPF, DKIM, and DMARC tools for authentication issues.