POP3 (Post Office Protocol version 3) works by allowing email clients to retrieve emails from a remote mail server to a local device. Here’s a step-by-step overview of how POP3 typically operates:
- Connection Establishment: The email client (e.g., Outlook, Thunderbird) initiates a connection to the POP3 server running on port 110 (or port 995 for SSL/TLS encrypted connections).
- Authentication: The client provides credentials (username and password) to authenticate itself to the POP3 server.
- Mailbox Access: Upon successful authentication, the client retrieves a list of available emails (messages) stored in the user’s mailbox on the server.
- Email Download: The client downloads selected emails from the server to the local device. By default, POP3 typically downloads the entire email including attachments.
- Message Deletion: Depending on the client settings, POP3 may delete messages from the server after they are downloaded to the local device. This behavior can be configured to either delete messages immediately or retain them on the server until explicitly deleted by the user.
- Session Termination: Once emails are downloaded, the client may optionally terminate the session with the POP3 server.
The POP3 protocol is used for retrieving emails from a remote mail server to a local client device. It operates on the application layer of the TCP/IP stack and uses a client-server architecture. POP3 enables users to access their emails offline once they are downloaded to the local device, unlike IMAP which typically keeps emails stored centrally on the server.
While POP3 was widely used in the past for accessing emails, its popularity has decreased in favor of IMAP (Internet Message Access Protocol) due to IMAP’s ability to synchronize emails across multiple devices. However, POP3 is still utilized in some scenarios, particularly by users who prefer to store emails locally and manage them without relying on server storage. Some email service providers and clients still offer support for POP3 alongside IMAP and other protocols.
POP3 primarily retrieves emails from a server to a client device. It does not handle sending emails directly. For sending emails, clients typically use the SMTP (Simple Mail Transfer Protocol) to communicate with an SMTP server, which then forwards the email to the recipient’s email server for delivery.
POP email works by allowing users to download emails from a remote mail server to their local device using the POP3 protocol. Once downloaded, emails are stored locally on the user’s device, enabling offline access and management. POP email clients periodically connect to the POP3 server to check for new emails and download them as per user settings. This method contrasts with IMAP, where emails are stored centrally on the server and synchronized across multiple devices, offering flexibility and real-time access to emails from any device connected to the internet.