List health
What is Catch-All (Accept-All) Domain?
A domain that accepts mail for any address, real or not, making verification uncertain.
A catch-all (or accept-all) domain is configured so its mail server accepts messages to any local part, even ones with no real mailbox behind them. As a result, a verification check cannot reliably confirm whether a specific address exists, because the server returns acceptance for everything during the SMTP conversation. Mail to a non-existent address on a catch-all domain may then be silently discarded or bounce later as a delayed rejection.
Why it matters for cold email
Catch-all addresses are a gray area for cold email because they pass basic verification yet may still be invalid, so sending to them raises the risk of late bounces and wasted volume, and disciplined senders treat them as a separate, lower-confidence segment.
Related terms
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