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◅ POP3/SMTP - Whats the difference?

POP3/SMTP - Whats the difference? ▻

POP3/SMTP - Whats the difference?

In article <3rmeus$c4a@altos.idiscover.co.uk>,
Carl Fooks <carl@idiscover.co.uk> wrote:
>POP3 is technically a more robost protocol.  If for some reason the SMTP
>software crashes after accepting the QUIT command and doesn't write it to
>disk you've lost your mail, however a POP3 mailbox will still have it in
>until you decide to delete it.

This is incorrect.

With both protocols, the host receiving the mail must take positive
action to cause the sending host to delete it.  In the case of SMTP,
this is the `250' response to the DATA command; in the case of POP, the
separate DELE command.

You might argue that this difference makes it slightly harder to write
a robust SMTP server, but there is no reason inherent in the standards
that SMTP should be a less reliable way of moving mail between hosts
than POP.

Note also this passage from STD 3 (RFC 1123); a conforming SMTP server
will not lose mail simply because of a software crash.

         When the receiver-SMTP accepts a piece of mail (by sending a
         "250 OK" message in response to DATA), it is accepting
         responsibility for delivering or relaying the message.  It must
         take this responsibility seriously, i.e., it MUST NOT lose the
         message for frivolous reasons, e.g., because the host later
         crashes or because of a predictable resource shortage.

Tim.
--
Tim Goodwin        | "If you're used to paint-by-number, a blank canvas
Public IP Exchange | can be unsettling at first." -- Larry Wall

Original headers:

From: tim@pipex.net (Tim Goodwin)
Newsgroups: uk.net
Subject: Re: POP3/SMTP - Whats the difference?
Date: 14 Jun 1995 13:13:14 +0100
Organization: PIPEX, 216 Science Park, Cambridge, England
Message-ID: <3rmjoq$hfj@pipe.pipex.net>
References: <1995Jun11.150023.339@rmcs.cranfield.ac.uk> <3rg5om$h4n@news.enterprise.net> <AKWNGFj030n@sktb.demon.co.uk> <3rmeus$c4a@altos.idiscover.co.uk>

△ uk.net △

◅ POP3/SMTP - Whats the difference?

POP3/SMTP - Whats the difference? ▻