Prove the difference between IMAP and POP3 by watching both

short · 45 min · Objective 1.3

Task

Configure one mailbox two ways and observe what each protocol does to the server copy, so that the difference is an observation rather than a definition.

Steps

  1. Create or choose a test mailbox and send it three messages. Record the count visible in the provider's web interface in lab/mail/before.txt.
  2. Configure a client using POP3 with the provider's documented server and port, and record the settings used in lab/mail/pop3.csv with header field,value covering server, port, security and whether leave-on-server was enabled.
  3. Collect mail, then check the web interface again and record the count in lab/mail/after-pop3.txt. Some providers decide this themselves: Gmail's own setting, "When messages are accessed with POP", keeps, archives or deletes its copy whatever the client asks, so record that setting too, or an unchanged count will look like POP never removes anything.
  4. Configure a second client using IMAP, record its settings in lab/mail/imap.csv with the same header, mark one message as read and move one to a folder.
  5. Check the web interface and a third device or the first client, and record in lab/mail/after-imap.md whether the read state and the folder move appeared elsewhere.

Verify

These checks run in a POSIX shell: Terminal on macOS or Linux, and on Windows Git Bash (it comes with Git for Windows) or WSL. A stock Windows PowerShell or Command Prompt has no awk or grep, so there the first line fails.

grep -c . lab/mail/before.txt
awk -F, 'NR>1 && NF>=2 {n++} END {print n" POP3 setting(s)"}' lab/mail/pop3.csv
awk -F, 'NR>1 && NF>=2 {n++} END {print n" IMAP setting(s)"}' lab/mail/imap.csv
grep -Eic '993|995|143|110' lab/mail/pop3.csv lab/mail/imap.csv
grep -Eic 'read|folder' lab/mail/after-imap.md

Four or more settings recorded for each protocol, at least one standard port number present, and the IMAP note describing state propagating. If the ports you recorded are the unencrypted ones, record why -- and whether the provider offered an encrypted alternative you did not use.

Notes

Use a disposable mailbox. POP3 with leave-on-server disabled will remove mail from the server, which is the behaviour this lab is demonstrating and is not something to demonstrate on a mailbox that matters.

This is an independent study companion for CompTIA A+ Core 1 220-1201 and is not produced by or endorsed by CompTIA.