Overview
SMTP (Simple Mail Transfer Protocol) is a fundamental communication protocol that enables email transmission across the internet. It serves as the standard mechanism for sending and routing email messages between servers.
Key Characteristics
Purpose
- Facilitate email message transmission
- Define rules for email communication
- Enable reliable message routing
Technical Specifications
- Operates primarily on port 25
- Uses a client-server communication model
- Supports both plain text and encrypted communications
Functional Mechanics
Email Transmission Process
- Email composition
- Message routing
- Server-to-server communication
- Final delivery to recipient’s mailbox
Security Considerations
- Supports STARTTLS for encryption
- Vulnerable to spam and spoofing
- Requires additional security layers
Related Protocols
- IMAP (Internet Message Access Protocol)
- POP3 (Post Office Protocol)
Historical Context
- Developed in 1982
- Part of the original internet communication protocols
- Continues to be a critical internet infrastructure component