Distinguish POP3 and IMAP using their standard non-TLS ports.
Which pairing is appropriate?
POP3 uses TCP 110 and IMAP uses TCP 143 for their standard plain connections.
Detailed explanation
POP3 TCP 143 / IMAP TCP 110Incorrect. It reverses POP3 and IMAP ports.
Incorrect. It reverses POP3 and IMAP ports.
POP3 TCP 110 / IMAP TCP 143Correct. These are the standard POP3 and IMAP ports.
Correct. These are the standard POP3 and IMAP ports.
POP3 TCP 25 / IMAP TCP 465Incorrect. Those are SMTP-related ports.
Incorrect. Those are SMTP-related ports.
POP3 UDP 110 / IMAP UDP 143Incorrect. POP3 and IMAP sessions normally use TCP.
Incorrect. POP3 and IMAP sessions normally use TCP.
Try it yourself
An example you can run in a temporary verification environment.
python3 -c "import socket; print(socket.getservbyname('pop3','tcp'), socket.getservbyname('imap','tcp'))"Expected result
110 143Key points
- POP3 110
- IMAP 143
- Both TCP
Notes
- Environment: Python 3 socket service database
- Command output formatting can vary slightly by distribution or tool version.
- Run the example in a temporary directory or process when possible.
Foundation review
Read the scope first
Check whether the command acts on the current shell, a new process, an existing process, or a file.
Verify the observable result
Use the supplied command and compare the output with the expected result.