What is Catch-all email?

A catch-all email domain is one whose mail server accepts mail for any address at the domain, whether or not that mailbox exists.

Also called: catch-all domain, accept-all server.

Most mail servers reject a message for a mailbox that does not exist, and that rejection is what SMTP verification listens for. A catch-all server says yes to every address, so asking it about jane@example.com and about a random string at the same domain gets the same answer. A verifier therefore cannot confirm or rule out a mailbox on a catch-all domain.

Verifiers label these addresses risky, accept-all or unknown rather than valid. That label is honest: the mailbox may be real and read every day, or the message may be accepted and silently discarded, or bounce later. Some domains are catch-all on purpose so that misspelled addresses still reach someone; others are configured that way by a hosting default.

The practical rule is to send to confirmed addresses first and to catch-all addresses separately, in small batches, watching the bounce rate on that batch alone. Mixing them into the main send lets an unprovable segment damage sender reputation for the whole list.

67Leads labels a catch-all address risky and never counts it as verified; the search shows risky addresses only when you ask for them.