TCP/IP is a communications protocol used by computers connected to the Internet to communicate.
TCP/IP refers to Transmission Control Protocol/Internet Protocol.
TCP/IP defines a standard for how electronic devices, such as computers, are connected to the Internet and how data is transferred between them.
TCP/IP mail syntax
Email is one of the most important applications of TCP/IP.
Your email program uses a different TCP/IP protocol:
Use SMTP to send mail
Use POP to download mail from the mail server
Connect to the mail server using IMAP