STARTTLSssä

STARTTLS is a command used in the Simple Mail Transfer Protocol (SMTP) to upgrade a plain text connection to an encrypted connection using Transport Layer Security (TLS). It allows email clients and servers to communicate securely over the internet, preventing eavesdropping and tampering with email messages. When a client initiates a connection to an SMTP server, it can send the STARTTLS command. If the server supports TLS, it will respond with a success code and initiate the TLS handshake process. This handshake establishes a secure, encrypted channel between the client and server, after which all subsequent communication, including authentication and message transfer, is encrypted. This is in contrast to implicit TLS, where the connection is established as encrypted from the very beginning. STARTTLS is widely used for securing email communications, including sending and receiving emails via protocols like POP3 and IMAP, in addition to SMTP. Its adoption has significantly improved the security and privacy of email over the internet.