Fresh POP / POP3 Interview Questions & Answers:

1. What do you know about POP3 session?

A POP3 session is created when a remote user connects to a mailbox on the POP3 mail server and ends when the remote user disconnects from the POP3 mail server.

2. What is an Email client?

An email client, email reader, or more formally mail user agent (MUA), is a computer program used to manage email.

Specifically, the term email client may refer to any agent acting as a client toward an email server, regardless of it being a mail user agent, a relaying server, or a human typing on a terminal. In addition, a web application providing message management, composition, and reception functionality is sometimes considered an email client.

3. What is SDPS?

Demon Internet introduced extensions to POP3 that allow multiple accounts per domain, and has become known as Standard Dial up POP3 Service (SDPS). To access each account, the username includes the hostname, as smith@hostname or smith+hostname.

4. What is XTND XMIT?

Irrespective of the mail retrieval protocol, email clients typically use the Message Submission flavor of the Simple Mail Transfer Protocol (SMTP) to send messages. POP3 contains a protocol extension, known as "XTND XMIT", that allows clients to transmit outbound mail. The Qualcomm qpopper and CommuniGate Pro servers and Eudora clients are examples of systems that optionally utilize the XTND XMIT methods of authenticated client to server email transmission.

5. What is STLS?

POP uses the Transmission Control Protocol on port number 110. Transmission may be encrypted using Transport Layer Security (TLS) or Secure Sockets Layer (SSL). This is negotiated in the POP3 protocol using the STLS command. Some clients and servers, such as Google Gmail, instead use the deprecated alternate-port method, which uses TCP port 995 (POP3S).

6. What is Post Office Protocol (POP POP/3)?

POP stands for Post Office Protocol, and is one of the technologies used for that all-important medium of communication: email. Like many other computer-related things, email requires a special language for mail to be received or sent. POP is one of the technologies that allows email sent from anywhere in the world to arrive in your inbox.