Simple Mail Transfer Protocol (SMTP)

What is Simple Mail Transfer Protocol (SMTP)?

SMTP is the most preferred protocol for sending email messages between email servers. The protocol follows the rules on the interaction between a program receiving email and a program sending email, including RFC 5321 and RFC 821.

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• Email Client
• Reply-To-Address
• SMTP Bounce Codes
• Opt-Out/Unsubscribe
• MX Lookup
• Commercial Email
• Canonical Name (CNAME)
• Email Deliverability