Mail helo

A classic!

MAIL HELLO is a command in the Simple Mail Transfer Protocol (SMTP) that is used to initiate a connection with a mail server. When a client sends a MAIL HELLO command, it is essentially saying "Hello, I'm here to send some email!"

Here's a breakdown of the command:

• MAIL: This is the command keyword.
• HELLO: This is the command argument, which is used to identify the client and initiate the connection.

When a mail server receives a MAIL HELLO command, it responds with a 220 status code, which indicates that the connection has been established successfully. The server may also provide some additional information, such as its name and version number.

Here's an example of a MAIL HELLO command and response:

Client: MAIL HELLO
Server: 220 mail.example.com ESMTP server (version 1.0)

After the connection is established, the client can then send other SMTP commands, such as RCPT TO to specify the recipient, DATA to send the email message, and QUIT to close the connection.