Catch-all domain

A catch-all domain (also called accept-all) is configured to receive mail for every possible address at that domain, whether or not a mailbox exists. Anything before the @ is accepted at the door. What happens next varies: the message may be routed to a shared inbox, silently dropped, or bounced later from inside the system.

For cold email this is a verification problem. Standard verification asks the mail server whether an address exists; a catch-all server always says yes. So an address that passes verification may still be dead, and the bounce arrives after you have sent, when it counts against your reputation. Catch-all is common among companies that route all mail through a filtering gateway, which includes many of the mid-sized firms B2B teams want to reach.

The honest way to handle it is to label the result as unknown and to decide how much unknown you are willing to send to. Seegnals verifies addresses on import, detects catch-all domains and reports them as unknown rather than pretending they are safe. If you choose to include them, keep the bounce shield on so a cluster of late bounces stops the campaign before it spreads.