What are the main differences between SMTP and POP3?

Differences between SMTP and POP3 in email communication:

SMTP (Simple Mail Transfer Protocol) and POP3 (Post Office Protocol version 3) are two different protocols used in email communication that serve distinct purposes:

1. Functionality: SMTP is used for sending emails from a client to a server or between servers, focusing on the sending aspect of email communication. On the other hand, POP3 is used for retrieving emails from a server to a client, concentrating on the receiving aspect of email communication.
2. Port numbers: SMTP typically uses port 25 for communication, while POP3 uses port 110. However, secure versions such as SMTPS (SMTP Secure) and POP3S (POP3 Secure) use ports 465 and 995 respectively.
3. Authentication: SMTP requires authentication for sending emails, ensuring that only authorized users can send messages. In contrast, POP3 authentication is needed for retrieving emails, securing access to the user's inbox.
4. Message handling: SMTP is involved in the transfer of emails from sender to recipient, whereas POP3 is responsible for downloading and storing messages on the client device.
5. Connection duration: SMTP communication is typically short-lived, where the server processes and forwards emails quickly. In contrast, POP3 sessions involve longer connections as users download emails and manage their inbox.

Understanding these key differences between SMTP and POP3 helps in efficiently managing email communication for both sending and receiving messages.