On a host using traditional mbox delivery, a message has been accepted and delivered to the local account carol. In which file does that delivered message now sit?
LPIC-1 Exam 102-500, objective 108. Essential system services medium
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The options
Correct /var/mail/carol
Correct. /var/mail is the incoming mail spool directory, holding one mbox file per account named after the user. Many systems keep /var/spool/mail as a compatibility symbolic link to it.
Not correct /var/spool/mqueue/carol
Wrong stage. The mail queue directory holds messages the MTA has accepted but not yet delivered, stored under generated queue identifiers, never under user names. A message here has not been delivered yet.
Not correct /home/carol/dead.letter
Wrong. dead.letter is where a mail user agent saves a message the sender abandoned or could not submit. It is a failed outbound draft, not delivered incoming mail.
Not correct /var/log/mail.log
Wrong. That is the MTA's log, recording one line per delivery event with queue ids and status. It records that the message was delivered; it does not contain the message.
Why
Separate the three locations a message passes through: the queue while the MTA still owes delivery, the mailbox once the delivery agent has written it, and the log which only records what happened. In mbox format the whole mailbox is a single file with messages separated by lines beginning From followed by a space, which is why concurrent writers must lock it. Maildir is the common alternative, storing one file per message under a directory such as ~/Maildir.
Where this comes from
- Cited
- manual page hier(7)
Practise this
Reading one question is not practice. The trainer will draw a short set from objective 108 and space the ones you get wrong.
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