Linux Interview Questions: Sendmail
The below questions are not my own, you can reach the author at -Ian! D. Allen - idallen@idallen.ca - http://www.idallen.com/A common misconception: the place/protocol you use to fetch your emailis the same place/protocol that you use to send your email: - sending email uses SMTP - reading email uses POP3 or IMAP - they can be completely separate machines http://wiki.mutt.org/?MailConceptQ: T/F, unlike POP3, SMTP can be used to both send and receive email.Q: T/F, unlike SMTP, POP3 can be used to both receive and send email. - may be completely different servers - though note POP-before-SMTP (SMTP-after-POP) requires coupling: http://tools.ietf.org/html/rfc2476 (section 3.3) "Requiring a POP [POP3] authentication (from the same IP address) within some amount of time (for example, 20 minutes) prior to the start of a message submission session has also been used, but this does impose restrictions on clients as well as servers which may cause difficulties. Specifically, the client must do a POP authentication before an SMTP submission session, and not all clients are capable and configured for this. Also, the MSA must coordinate with the POP server, which may be difficult. There is also a window during which an unauthorized user can submit messages and appear to be a prior authorized user."Q: Describe briefly how POP-before-SMTP works to authenticate an SMTP session.MUA - Mail User Agent (email client) - the user's interface to the protocols...
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