Mail Server Protocols
In this section, we will take a look at the protocols used in an Email server.
- SMTP: Simple Mail Transfer protocol
- POP3: Post Office Protocol
- IMAP: Internet Message Access Protocol
1. SMTP (Simple Mail Transfer protocol):
This protocol communicates through port 25. This protocol is used when email is delivered from email client to server. E.g. Outgoing emails from outlook server to an external email server.
2. POP3 (Post Office Protocol):
This protocol communicates through port #110. This allows email client to download email from the server. This protocol downloads all the emails and then deletes the emails from the server. E.g. A desktop mail client can use POP3 protocol.
3. IMAP (Internet Message Access Protocol):
This protocol allows email clients to download emails from the server. Unlike POP3, it doesn’t delete the email from the server. If IMAP is used, more space needs to be provisioned on the server.
IMAP is used when there is a need to access the email from a variety of clients like desktop, mobile, tablet etc. Since the emails are always stored on the server, unless deleted explicitly, it could be accessed from different clients.