ePosti

Eposti is a term used for electronic mail, a system for sending and receiving messages over a computer network, typically the Internet. It enables users to compose messages, attach files, and have them delivered to one or more recipients across different networks. Eposti uses a store-and-forward model in which messages travel from a sender’s client to a mail transfer agent, may pass through multiple servers, and are stored in the recipient’s mailbox until retrieved by a mail client.

How eposti works is centered on a set of interoperable protocols. The sender’s mail client submits the message to a mail transfer agent using the Simple Mail Transfer Protocol (SMTP). The message is routed through one or more MTAs across the Internet until it reaches the recipient’s mail delivery system, which stores it in the mailbox. The recipient then accesses the mailbox with a mail user agent using IMAP or POP3. Core standards for eposti and message formatting include RFC 5321 (SMTP), RFC 5322 (Internet Message Format), and related specifications. Additional protocols and extensions handle retrieval, security, and mailbox management.

Security and privacy considerations include encryption of transport with TLS, digital signing and encryption with S/MIME or OpenPGP, and sender authentication mechanisms such as SPF, DKIM, and DMARC. The system is also subject to spam, phishing, and data privacy concerns, prompting ongoing developments in filtering and user controls.

Today, eposti remains a foundational tool for personal and professional communication, supporting text, attachments, and extensive archival capabilities, accessible via desktop clients, mobile apps, and webmail interfaces.