Free email blacklist (DNSBL) check. Test a sending IP or domain against the major spam blocklists, Spamhaus ZEN and DBL, SpamCop, Barracuda, PSBL, UCEPROTECT, SORBS, Mailspike, SpamRats, SURBL, and more, in one sweep. We query through our own recursive resolver, so Spamhaus and URIBL return real answers instead of the refuse-shared-resolver codes that make other tools show false listings, and we decode each list's return codes so a residential-policy marker (Spamhaus PBL) is never reported as a spam accusation. Runs from our London probe.
A DNSBL (DNS-based blocklist) is a list of sending IPs or domains that a blocklist operator considers a spam source. Receiving mail servers query these lists in real time during delivery, so a single listing can send your mail straight to spam or bounce it. A check reverses your IP and queues it as a DNS lookup against each list; a returned 127.0.0.x answer means listed, no answer means clean. This tool sweeps the major lists at once, including Spamhaus ZEN and DBL, SpamCop, Barracuda, PSBL, UCEPROTECT, SORBS, Mailspike, SpamRats, and SURBL.
Spamhaus and several other lists refuse queries that arrive through large shared resolvers like public DNS, returning a special error code that many tools misread as a listing. That is why one checker says you are on Spamhaus while another says you are clean. This tool queries through its own dedicated recursive resolver, so those lists return real answers instead of refuse codes. It also decodes each list's specific return codes, so a residential-policy marker such as Spamhaus PBL (which simply notes an IP is dynamic, not a spam accusation) is never reported as a spam listing.
If you are listed, note that IP and domain reputation are separate: a clean IP can still send from a listed domain, and vice versa. Check both, and use the operator's own delisting page to request removal once the underlying cause is fixed.
An email blacklist, or DNSBL, is a published list of IP addresses or domains flagged as spam sources. Receiving mail servers query these lists during delivery and may reject or spam-folder mail from a listed sender.
Lists like Spamhaus refuse queries from large shared public resolvers and return a special code that some tools misread as a listing. Querying through a dedicated resolver returns the true answer, which is why results differ between tools.
The PBL (Policy Block List) simply marks IP ranges that should not send mail directly, such as residential connections. It is a policy marker, not an accusation of spamming, and this tool reports it as such rather than as a spam listing.
First fix the cause, such as a compromised account, an open relay, or a misconfigured mail server. Then use the delisting page on the specific blocklist's website to request removal. Delisting before fixing the cause usually results in a relisting.
