What is the function of SMTP (Simple Mail Transfer Protocol)?

SMTP, or Simple Mail Transfer Protocol, is primarily designed for sending and relaying email messages between servers and clients. Its primary function is to facilitate the transfer of email content from the sender's email client to the recipient's mail server, enabling reliable electronic communication.

The protocol operates over the internet and ensures that email messages are correctly routed to the right destination through a series of defined commands and responses between the client and server. While it plays a critical role in sending emails, it does not handle the retrieval of emails from the mailbox or any web-related tasks, which are managed by other protocols like POP or IMAP for receiving mail and by HTTP for web interactions.

Furthermore, SMTP does not resolve domain names; that task is performed by the Domain Name System (DNS). Similarly, assigning IP addresses is done through Dynamic Host Configuration Protocol (DHCP) or manual configuration, and is not within SMTP's scope. Understanding SMTP's dedicated role within email communication is crucial for grasping how data is transferred across the internet.