Blacklist Check
Test a domain’s mail servers — or any IP address — against 83 IP blacklists and 17 domain blacklists.
Try turbosec.io, gov.uk or 127.0.0.2
How this works
All at once
Blacklists are queried in parallel over UDP rather than one after another, so a full sweep of 83 lists across several addresses takes seconds instead of minutes.
Refusals are not listings
Several lists answer 127.255.255.254 when a query arrives from a public resolver. That means “ask from your own resolver”, not “you are blacklisted” — we report it as refused.
Dead lists are excluded
When a blacklist shuts down its domain is often parked and answers positively for every query. 38 retired zones are deliberately not queried, because checkers that still include them report false hits.
Every zone that is queried first gets a control question whose answer is known in advance — a name that could never legitimately be listed. A list that reports the control as listed is answering positively for everything, and its results are withheld rather than shown. Only a handful of operators publish a positive testpoint as well; where one exists we also confirm the list can still say "yes", which is the only way to tell a working list from one that has quietly stopped answering.
5 further zones are alive but will not answer us, and are not queried at all:
- Spamhaus ZRD — zrd.spamhaus.org Only published via Spamhaus DQS, never on the public mirrors. A free DQS key would enable it.
- URIBL multi — multi.uribl.com URIBL answered its own testpoint with 127.0.0.1 (nameserver blocked) in September 2026. Not queried, because a refusal is not a verdict.
- URIBL black — black.uribl.com Same operator and same block as URIBL multi.
- URIBL grey — grey.uribl.com Same operator and same block as URIBL multi.
- URIBL red — red.uribl.com Same operator and same block as URIBL multi.
This is not the same as a list being retired. These are working, well-regarded lists that block third-party resolvers or require a paid feed. Their absence means this page is checking less ground than the zone count alone suggests, which is worth knowing before reading a clean result as an all-clear.
What a listing costs you
Results say which list found you and why, mark the handful that large receivers actually consult, and link straight to each delisting form.