State the Differences Between IMAP, POP, and SMTP Protocols

The tutorial explains the differences between commonly used protocols named – POP3, IMAP, and SMTP. These emails are used to send and receive emails between servers and clients. To completely understand these protocols, it is necessary to know their functions.

The basic difference between is –

  • IMAP – is used to access emails on web server
  • POP3 – is used to receive emails from server to local client
  • SMTP – is used for sending emails

Let is know more about these protocols –


SMTP i.e. Simple Mail Transfer Protocol. This allows transmitting email messages over the internet. Basically, the protocol handles outgoing emails. It is used between servers to send emails to a server and also used by servers to push email to another server. There are other protocols available but SMTP is one of the most common protocols among them.

SMTP works basically on three ports –

Port 25– default SMTP non-encrypted port

Port 2525– it is opened for all SiteGround Servers in case port 25 is filtered and you need to send non-encrypted emails with SMTP

Port 465– used to send messages using SMTP securely

POP or POP3 (Post Office Protocol)

POP3 is used to receive emails from server to local client. When you use POP3 to connect your email account, the emails are downloaded locally on your system and these are removed from the email server. By this, users can reduce the storage space of their web server by saving the messages on the local computer.

POP3 basically works on two ports –

Port 110– default POP3 non-encrypted port

Port 995– this port is needed if you want to connect using POP3 securely


IMAP is extended as Internet Message Access Protocol, used to receive email messages from the internet. By IMAP protocol, you can receive your emails on more than one system as the received messages will remain on the email server.

IMAP works on two ports –

Port 143– it is the default IMAP non-encrypted port

Port 993– you need this to connect using IMAP securely

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