A user wants a mail program to download messages onto one PC and remove them from the server. Which port does that retrieval protocol use?
Select an answer to reveal the explanation.
Short Explanation
The user wants the letters taken out of the post office and filed on one desk. You use POP3 on TCP 110. Leaving the mail up for every device, handing mail between servers, and browsing the web are different jobs.
Full Explanation
POP3 is the retrieval protocol that downloads messages to the client, and it uses TCP port 110. That matches a user who wants mail on one PC and removed from the server. IMAP uses TCP port 143 and is built to leave mail on the server for several devices. It is the opposite of downloading and deleting. TCP port 25 is SMTP, used to send or transfer mail, not to download a mailbox. TCP port 443 is HTTPS. It does not retrieve and delete mail. Exam caveat: a mail program can be told to leave copies on the server even with POP3. The protocol this user described is still POP3, not IMAP. Operational check: configure POP3, download a test message, and confirm it is no longer in the server mailbox. Download a test message and confirm it is gone from the server mailbox. Note the result on the ticket. Confirm a second message does not remain on the server after the download.