Port 143 is a standard network port primarily used for the Internet Message Access Protocol (IMAP).
Understanding Port 143 and IMAP
According to the list of well-known TCP and UDP port numbers, port 143 is designated for IMAP.
- Protocol: Internet Message Access Protocol (IMAP)
- Transport: TCP (Transmission Control Protocol)
- Purpose: Management of electronic mail messages on a server.
Unlike protocols like POP3 (Post Office Protocol v3), which typically downloads messages from the server to a local device and often deletes them from the server, IMAP allows users to manage email directly on the server. This means that emails are stored on the server, and users can access, organize, and synchronize their mailboxes across multiple devices. Actions performed on one device (like marking an email as read, moving it to a folder, or deleting it) are reflected when accessing the mailbox from another device.
Port Information Overview
Here's a snippet from the provided reference showing the details for port 143:
| Port | TCP | Description |
|---|---|---|
| 143 | Yes | Internet Message Access Protocol (IMAP), management of electronic mail messages on a server |
This table, sourced from resources like the List of TCP and UDP port numbers on Wikipedia, confirms the assignment of port 143 to IMAP.
In summary, when an email client connects to an email server using the standard, non-encrypted IMAP protocol, it typically connects to port 143 on the server to manage the emails stored there. For secure IMAP connections, port 993 is commonly used with SSL/TLS encryption.
