Ask The STI Help Desk –
What Is an SMTP Server and a POP3 Server?
By Sierra Tel Internet & Cornerstone Publishing

July 14, 2005

Question: What is an SMTP server and how is it different than a POP3 server?

Answer: Both types of servers have to do with handling email messages, and they are both usually located at the Internet Service Provider’s facility. The acronym "SMTP" stands for Simple Mail Transfer Protocol. It is used to forward each of your email messages to the correct destination. The acronym "POP3" stands for Post Office Protocol Version #3. The POP3 server is used to collect incoming email destined for an Internet Service Provider's customers.

Here's how the SMTP and POP3 servers work: After you connect to the Internet, open up your email client and retrieve your email messages, your email program logs on to the POP3 server at your ISP’s location in order to retrieve email messages that are addressed to you. When you send an outgoing email, your email program sends the message to a SMTP server located at your ISP, which then forwards it out over the Internet. The message is collected at the recipient's POP3 server located at his/her ISP until the recipient retrieves the message to read it.

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