Differences between POP3, IMAP, SMTP and HTTP

POP3, IMAP, SMTP and HTTP


First we need to know what the individual abbreviations exactly mean, in order to understand how our E-Mail-accounts work:




POP3: Post Office Protocol Version 3. POP3 is an ASCII transfer protocol that uses commands by default and sends them to port 110. POP3 requires no persistent connection to the mail server. The connection to the server is built and terminated via the client.



IMAP: Internet Message Access Protocol. IMAP is an application log, which allows the access to E-Mails located in a mailbox on the mail server. IMAP also manages received mail. Therefore, IMAP uses port 143.



SMTP: Simple Mail Transfer Protocol. SMTP is a protocol of the datagram of Protocol for exchanging E-Mail messages in computer networks. The SMTP server uses the ports 25 and 587 to connect to the mail server.



HTTP: Hypertext Transfer Protocol. HTTP is a protocol for transferring data via a network. It is primarily used to load Web sites from the World Wide Web into a Web browser. HTTP uses port 80.



Differences between POP3, IMAP and HTTP


To better understand how your mail account works, we now want to different transfer methods and protocols from each other.


The POP3 protocol picks your messages from an E-Mail Server up. You can decide whether to save or delete the messages on the server.


Usually the SMTP Protocol is in charge of sending E-mails.
This includes not only the sending of messages from the E mail client of the user to the server of the provider, but also the forwarding of messages from server to server within the Internet or corporate network. Like POP3, SMTP is a text-based protocol.


IMAP leaves the files (mails) on the mail server of the provider, until the client deletes them for good. The file must not be saved by the user itself, because the provider is responsible for the backup of the data. You can access your messages from each computer. When you log on by the E mail server, the existing data gets adjusted with those on your computer. While reading, writing and answering messages, a connection to the E-Mail Server must be established.



HTTP is a web based E-Mail service. If you have such an E-Mail provider account, you need a Web browser to access your E-Mails and retrieve them.
HTTP is applied in the graphical portion of the Internet, the World Wide Web. Web-based E-Mail providers often offer the possibility to collect E-Mail messages via POP3 or IMAP.