General IMAP question

Joseph Tam jtam.home at gmail.com
Fri Sep 1 01:39:08 EEST 2017


"Scott Techlist" <techlist06 at msws.org> writes:

> Currently my POP users have a max mbox size but that is how much it
> will store before they "come get it".  I ensure they have at least one
> device set to delete from the server periodically (i.e.  1 week).  So
> users with multiple devices get their mail duplciated on their devices
> and at least one devices keeps the server emptied so their mbox does
> not hit any limits.

Traditionally, POP was a store and forward protocol.  The client would
download all the message in INBOX, them empty the mailbox.  Nowadays,
many POP users configure their clients to "Leave on server mode", which
essentially accumulate on the server.  The client may or may not also
keep a cached copy.

> As I understand it, when using IMAP, the user's messages are
> perpetually stored on the server.

IMAP is oriented as a remote mail service (client fetches and manipulate
mail data on a remote server), so yes, messages are meant to remain on
the server until deleted.  There are probably some clients that cache
local copies, but the remote server is considered canonical, so that
local copies are deleted if the remote copies disappear.

> How do other's deal with this? Am I misunderstanding something? As
> popular as it seems to be, these seem like big hurdles to overcome.
> Appreciate some help for a IMAP noob.

What problem are you trying to solve?  Is there a particularly compelling
reason for you to move to IMAP (if not, stay with POP3)?  You want to
curtail space usage by users?  You want to force users to retain client
side copies of the messages?

(Mind you, you'll still could have the same problem with POP -- there's
nothing you can do to enforce the client to download/delete messages.
Whether you use IMAP or POP3, you'll probably need some client side
set up.)

Joseph Tam <jtam.home at gmail.com>


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