Networking Fundamentals

Simple Mail Transfer Protocol

Simple Mail Transfer Protocol (SMTP) generally provides two functions. It allows you to send emails from your email client, such as Outlook, to your email server. It also allows your email server to transfer mail from your email server to another email server. Both of these functions are performed over port 25.

Exam tip: Although the S in SMTP stands for Simple, I quite often say to myself that it stands for Send as in Send Mail. While not factually correct, it reminds me of its purpose compared to IMAP and POP, which are used to receive emails.