What SMTP command is used to specify the recipient's email address?

The command that specifies the recipient's email address in the Simple Mail Transfer Protocol (SMTP) is "RCPT TO." This command is used during the SMTP transaction to indicate the email address to which the sender is addressing the message. When the sender issues the RCPT TO command followed by the recipient's email address, the SMTP server acknowledges this information as part of the process for routing the email.

Understanding this command is crucial in the SMTP protocol as it is a key part of the process for delivering email. It directly determines to whom the email is intended and sets up the necessary routing to ensure the message reaches the correct inbox.

In contrast, other commands serve different purposes within the SMTP protocol. The HELLO command is typically used to identify the sending server during the connection process. The MAIL FROM command specifies the address of the sender, and the DATA command is used to send the actual content of the email after establishing the recipient and sender information. Each command plays a vital role, but only RCPT TO specifically handles the recipient's address.