SMTP Handshake
The conversation with a mail server (HELO, MAIL FROM, RCPT TO) used to probe whether a mailbox exists without sending an actual message.
Why it matters for email security
Understanding smtp handshake helps you build signup flows that resist fake accounts, disposable inboxes and automated abuse. VeriShield Edge operationalizes this signal as part of its transparent 0-100 fraud score.
Related concepts
Explore the full glossary or the domain directory to see these signals applied to real domains.