Re: Misc minor POP3 issues

John Gardiner Myers <jgm+@cmu.edu> Sat, 04 June 1994 04:55 UTC

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Date: Sat, 4 Jun 1994 00:53:28 -0400 (EDT)
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From: John Gardiner Myers <jgm+@cmu.edu>
To: POP3 IETF Mailing List <ietf-pop3+@andrew.cmu.edu>
Subject: Re: Misc minor POP3 issues
In-Reply-To: <19940603231837.AAA9697@rome.software.com>
References: <19940603231837.AAA9697@rome.software.com>
Beak: Is

Mike@Software.com (Michael D'Errico) writes:
> This was one of the original messages sent out to this list.  Sorry
> about taking so long to respond to it.

It's appropriate to deal with the bigger issues first.  Now we're in
the home stretch.

> This is an issue related to the broken TCP connection argument we've
> been having.  I implement a timeout which defaults to 10 min. and is
> configurable.  If the server times out, it sends a "-ERR" message and
> closes the connection.  The UPDATE state is not entered, and no messages
> are deleted.  Does this seem like a reasonable thing to do?

An autologout timer should certainly do the same thing with respect to
the UPDATE state as a broken TCP connection.

If we permit an autologout timer, we should specify a minimum value
for it so clients can know how often to send NOOP keepalives.  For
comparison, the shortest permitted autologout timer in IMAP is 30
minutes.

A potential problem: When the server times out, if it sends an "-ERR"
message, a client may erroneously deduce that the error was caused by
the next command it tries.

I have seen a situation where a PC crashed while holding an open POP3
connection.  The connection thus never got closed and the maildrop was
left locked.  An autologout timer would solve this problem.

> Why not deprecate TOP and replace it with the HEAD command (for "headers")
> which would just return the message headers?

I think in this case it is easier to change the wording to match
reality than vice versa.  State that commands are 3 or 4 characters
long and are possibly followed by one or more arguments.

-- 
_.John G. Myers		Internet: jgm+@CMU.EDU
			LoseNet:  ...!seismo!ihnp4!wiscvm.wisc.edu!give!up