Free tool

Blacklist check

A domain doesn't have a reputation — the addresses that actually send its mail do. This reads the domain's SPF record, pulls out the addresses it authorizes (not its inbound mail servers, which are a different thing and usually belong to a provider that's never listed), and checks those against public blocklists.

Scope, before you run it: it checks SpamCop, Barracuda, PSBL. Spamhaus ZEN can't be queried from here — it refuses requests from public DNS resolvers, which is what this tool uses — so it always renders as unavailable. And it only checks single sending addresses (an ip4: entry with no range, or a bare IP). Shared provider ranges are named but not sampled — testing one address out of a /24 would be a guess about the other 255, not a check.