CheckMXCatch-all email checker
Understand a risky result before you decide what to do with an address.
What is a catch-all domain?
A catch-all domain accepts mail addressed to recipients even when a matching mailbox may not exist. It may route those messages to one mailbox, or accept them before deciding what happens next.
Why verifiers report catch-all as risky
Verifiers, including CheckMX, cannot use acceptance alone to distinguish a real mailbox from an invented recipient on a catch-all domain. Risky means the individual inbox is uncertain; it does not mean every address on the domain is invalid.
SMTP acceptance is not a delivery guarantee
An SMTP recipient check asks a mail server whether it will accept an address. It does not deliver a real message. The server can accept that recipient and later bounce, discard or filter the message. Delivery and inbox placement remain separate questions.
What you can do
- Review spelling and how you obtained the address.
- Ask the contact to confirm it through an existing channel.
- Keep risky addresses separate and review them before use.
- Honor opt-outs and use addresses only where you have a valid basis to contact the person.
Inspect the domain, then check an address
The DNS lookup below shows mail routing and authentication records. It cannot detect catch-all behavior. The email demo can report a catch-all signal when the verifier can determine it.
Look up a domain
Free email check
Syntax, MX, SMTP and catch-all checks, with context.
The demo allows a few free checks per day. A check may return unknown if the server cannot be reached or gives no answer. Email checks are free.
For a longer explanation, read the guide to catch-all emails.
Frequently asked questions
Can MX records tell me whether a domain is catch-all?
No. MX records identify mail servers. Detecting catch-all behavior requires recipient checks; DNS alone cannot confirm it.
Does catch-all mean an email address is invalid?
No. The mailbox may exist, but the server also accepts other recipients, so acceptance cannot confirm this specific inbox. CheckMX reports this uncertainty as risky.
Does SMTP acceptance guarantee delivery?
No. A server can accept a recipient during a check and later reject, discard, filter or bounce a real message. Acceptance does not guarantee delivery or inbox placement.
What should I do with a catch-all result?
Keep it separate from confirmed addresses, check the spelling and source, and ask the contact to confirm their address through an existing channel. Avoid assuming that a risky result is permission to send.
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