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IMAP4 ( Internet Message Access Protocol version 4) vs POP3 (Post Office Protocol version 3)

POP3 (Post Office Protocol Version 3)

Post Office Protocol version 3 i.e. POP3 is used as message retrieval protocol to access internet based email account. It is described in RFC 1939. Client initiates TCP connection to POP3 server on port 110. Once the connection is established client send both username and password information to the server, once this gets validated user can access the mailbox. POP3 client sends 4 character commands to the server. Server responds small no. of alphabetic responses.All these commands and responses are not visible to the email user.

With POP3 user can delete and download the mails. User can also list the mails. But user can not alter or change the contents of the email on the server. To do so, user need to first get the contents on local client machine and then modification can be done. This causes delay and also increases network traffic due to content downloading function.

Features of POP3

  • In POP3, all the emails are downloaded to the local computer, and once all the emails are downloaded, they are deleted from the server.

  • Downloaded emails can be accessed offline also.

  • Emails are not synchronized between different devices, which means if we set up our email using our mobile phone with POP3, those emails will be downloaded completely on your mobile phone, and cant be accessed from other devices.

Choose POP if:

  • You only access your mail from a single device, and never plan to access it from another.

  • You need constant access to all your email.

  • Your don't have a consistent connection to the internet.

  • You have limited server storage.

IMAP4 (Internet Message Access Protocol version 4)

IMAP addresses the limitation of POP3 and it allows various functions such as move, delete and view messages without even copying the contents on the local machine. Hence the major difference is that POP3 helps download the contents and then operate on the contents on client machine locally, while IMAP4 helps operate on the contents directly in the server without downloading to the local machine.

Features of IMAP

There are some features of IMAP, which are as follows:

  • Emails are stored on the server instead of an email client.

  • Sent messages are also stored on the server-side in the sent folder, which allows us to check the sent email from anywhere.

  • You can synchronize the messages and access youremail from multiple devices.

  • It is more complex and flexible.

  • It helps to download email data from AOL to your device or software.

  • We will not lose our emails even if our device is destroyed or stolen.

  • The server also saves the status of the emails, such as read, unread, or replied. It helps to check the status of an email from any computer or device.

  • When we start downloading emails using IMAP, it firstly shows the header (Sender, date, email subject); at that instant, we can decide whether to download the email or not.

Choose IMAP if:

  • You want to access your email from multiple devices.

  • You have a reliable and constant internet connection.

  • You want to receive a quick overview of new emails or emails on the server.

  • Your local storage space is limited.

  • You are worried about backing your emails up.

Difference Between POP and IMAP


POP is a simple protocol that only allows downloading messages from your Inbox to your local computer.

IMAP is much more advanced and allows you the user to see all the folders on the mail server.

The POP server listens on port 110, and the POP with SSL secure(POP3DS) server listens on port 995

The IMAP server listens on port 143, and the IMAP with SSL secure(IMAPDS) server listens on port 993.

To read the mail it has to be downloaded on the local system.

The mail content can be read partially before downloading.

The user can not organize mails in the mailbox of the mail server. And The user can not create, delete or rename email on the mail server.

The user can organize the emails directly on the mail server. And The user can create, delete or rename email on the mail server.

It is unidirectional i.e. all the changes made on a devices does not effect the content present on the server.

It is Bi-directional i.e. all the changes made on server or device are made on the other side too.

It does not allows a user to sync emails.

It allows a user to sync their emails.

It has two modes : delete mode and keep mode.

In delete mode , the mail is deleted from mail box after retrieval.

In keep mode , the mail remains in the mail box after retrieval.

Multiple redundant copies of the message are kept at the mail server, in case of loss of message of a local server, the mail can still be retrieved

It is fast

It is slow as compared to POP3

Also Read:

AMQP (Advanced Messaging Queuing Protocol) vs MQTT(Messaging Queuing Telemetry Transport)

ARP(Address Resolution Protocol) vs RARP (Reverse Address Resolution Protocol)

NAT (Network Address Translation) vs PAT(Port Address Translation)

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