Email servers communicate with each other using the Simple Mail Transfer Protocol (SMTP) to send and receive mail. The SMTP protocol transports email messages in ASCII format using TCP.

• 邮件伺服器使用简单邮件传输协定(SMTP)彼此通讯来传送及接收邮件。SMTP协定使用TCP传送ASCII格式的电子邮件讯息。