Catch-All Email Checker
Check if an email domain is configured as catch-all. Catch-all domains accept emails to any address, making validation unreliable.
Quick Answer
To check if an email domain is catch-all, you need to test whether the mail server accepts emails to non-existent addresses. The most reliable method is SMTP verification: connect to the mail server, say HELO, then try to send to a random address like test123456@domain.com. If the server accepts the email (returns 250 OK) instead of rejecting it (550 mailbox not found), the domain is catch-all. Our tool performs this check automatically by sending a test to a random address at the domain. Catch-all domains are common among businesses — they configure their mail server to accept all emails as a safety net for misspelled addresses. However, catch-all detection makes email validation less reliable because you cannot confirm whether a specific mailbox exists just from the server acceptance response.
Source: RFC 5321, SMTP Standards
Understanding Catch-All Domains
How Catch-All Works
When a domain is catch-all, the mail server accepts emails to ANY address@domain.com, even if the mailbox doesn't exist.
Validation Limitations
Catch-all detection can only flag the domain — it cannot verify if a specific mailbox exists without SMTP verification.
Common in Business
Many companies use catch-all to avoid losing emails due to typos (e.g., jsmith@ vs johsmith@).