POP 3

Post Office Protocol version 3 is an Application Layer protocol for retrieving emails from a mail server like IMAP. While SMTP is used for sending emails, these protocols handle receiving and managing them on client devices.

POP3 works on Ports 110 and port 995 for encrypted communication via SSL/TLS. The main features it has are:

• Downloads emails from the server to the client’s device

• Best for single-device email access

• Once emails are downloaded, they are typically removed from the server

• Simpler than IMAP and requires less storage on the mail server

POP3 uses a series of commands to interact with mail servers. Some of them are:

• USER: Identify a user

• PASS: Authenticate using password

• STAT: Request the number of emails on the server

• LIST: Request the number and size of all emails

• RETR: Request to show an email by ID

• DELE: Request to delete an email by ID

• CAPA: Request to display the server capabilities

• RSET: Request to reset the transmitted information

• QUIT: Close the connection