SMTPstandardit

SMTPstandardit is the collective set of standards and best practices that define the operation of the Simple Mail Transfer Protocol (SMTP) and related mechanisms used to send and relay email over the Internet. It encompasses the core SMTP protocol, message formatting rules, and service extensions that enable features such as secure transmission, large message handling, and internationalization. The standards are published by the Internet Engineering Task Force (IETF) in the RFC series, with the core protocol defined in RFCs that describe the basic command set, responses, and session state, and subsequent RFCs that introduce enhancements under the Extended SMTP (ESMTP) framework. Security is a key focus, with STARTTLS offering opportunistic encryption of SMTP sessions and various authentication and integrity mechanisms evolving over time. Internationalization and character support are addressed by extensions that permit non-ASCII content under controlled conditions. Email delivery systems implemented according to SMTPstandardit include mail transfer agents, mail submission agents, and gateways, which exchange messages using the agreed command set, response codes, and timing rules. The standardization effort also covers delivery status notifications, error reporting, and compatibility handling to support interoperation across diverse servers and networks. While SMTPstandardit provides interoperability, real-world deployments must contend with security threats, misconfigurations, and evolving anti-spam practices. Related topics include DKIM, SPF, and DMARC, which operate alongside SMTPstandardit to improve mail authentication and delivery.