Blocklist check
A blocklist cannot tell you it has stopped working. A zone that was shut down answers nothing, which is the same answer it gives for an address that is not listed, so every checker still querying it reports the whole internet as clean. One that was retired by wildcarding answers yes to everything, which reports the whole internet as listed. Both are common, and neither is visible without asking the list about itself first.
An address goes to the address lists and a domain to the domain lists: they answer different questions. Nothing you type is sent to this site. The lookups run from your browser.
Checks are rate limited. Run several in quick succession and a checkbox may appear below asking you to confirm you are a person. The remaining lists are checked either way.
Lists that have stopped working
A blocklist that shuts down rarely announces it. The zone is left in place, or withdrawn, or repurposed, and the failure only shows up as an answer that looks ordinary.
- It answers nothing. SORBS was decommissioned in 2024 and its zone stopped answering. Silence from a dead list is identical to silence meaning you are not listed.
- It answers everything. AHBL wildcarded its zone when it closed in 2015, deliberately, to force the remaining traffic away. It still answers yes to every name put to it.
- It answers on another convention. Some reputation services publish over the same interface without using the same return codes, so an answer that parses as a listing may not be one.
A list in any of those states is reported here as unchecked rather than as clean, and named, so you can see what was and was not covered. RFC 5782 defines the entries that separate a working list from a broken one.