POP3 stands for Post Office Protocol 3.It is a most recent version of a standard protocol which is used for receiving emails. It is a client/server protocol which receives emails from a remote server to a local email client.POP3 allows you to download the messages from the mail server. You can download the email messages and read them when you are offline. Once you download the email locally, it will get automatically deleted from the server to reduce the space of your email account on the server. It means that it will not give you the best results when you fetch your email account from different places. RFC well described POP3 in 1939. It uses Port 110 as a default port. It uses a series of commands to retrieve the message from the mail server. Once you download the messages with the help of POP3, it will get automatically saved to your local computer. You can make some implementations to keep your email for some time. It is the reason why POP3 is also known as “Store and Forward Service.” Learn more about IMAP tools here.
By default, POP3 works on two ports: –
- Port 110: – It is a non-encrypted port for POP3.
- Port 995: – This port is used when you securely connect with POP3.
While retrieving a message from POP3 server, the client needs to build a TCP session using TCP port 110 Sand identifies itself to the computer which issues a series of POP3 commands.
- Stat: – stat command asks the server about the number of messages to be retrieved.
- List: – The list command determines the size of the message to be retrieved.
- RETR: – This command extracts individual words d. Quit: Ends the POP3 session.
The process of Mail accessing by POP3: – The process of mail accessing through POP3 includes the following steps: –
- POP3 is client/server software. Therefore, the client POP3 is installed in the receiver’s computer, and the server POP3 software is installed on the mail server computer.
- The communication procedure of the POP3 is similar to SMTP, and it uses ASCII characters.
- The process of the communication starts with the reading of the mail.
- When you read an email, it calls up the mail server and establishes a TCP connection with the message transfer port at Port 110.
- After creating a secure connection, the POP3 includes a sequence of three stages: Authorization, Transactions, and Update.
Authorization: -You will be authorized to deal with user log in just by sending client name and password.
Transactions: – It collects the emails and marks them to delete from the mailbox.
Update: – Update options delete the read emails.
- After logging in, it allows you to send a list of commands to its mailbox. One message will be displayed per line until end along with its length by the server.
- The client of POP3 can retrieve the messages by using the RETR command and mark them for deletion by using del command.
- Once all the messages get retrieved, the client gives the quit command to the POP3 to end the transaction state. You can now enter the update state for further working.
- Once all the messages have been retrieved, they get deleted from the mail server. It will send a reply and breaks the TCP connection. We hope that you have got enough information on, what is POP3 all about?