What is SMTP handshake validation?
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Ever wonder how validators actually confirm your email address exists without sending a real message? That's what SMTP handshake validation does.
A validator connects to the recipient's mail server and walks through the first few steps of the SMTP conversation. It says hello (HELO), claims it's sending from your domain (MAIL FROM), and asks if a specific mailbox exists (RCPT TO). Then it stops. It doesn't actually send a message. Instead, the server's responses tell the validator everything. If the server says "yes, that mailbox is valid," you've got a confirmed address. If it says no, that's a bounce.
The beauty here is speed and safety. The validator gets a definitive answer in milliseconds without filling anyone's inbox with test emails. This is especially important if you're validating addresses before sending. Want to see how your domain handles validation requests? Check your SPF setup to make sure your infrastructure supports clean validation.
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