Subject: RE: IMAP v. POP (Was: The utilitiy of IP is at stake here)

From: "Michel Py" <[email-masked]>
Date: Wed, 4 Jun 2003 09:25:34 -0700

Terry,

> Terry Gray wrote:
> In contrast, I suspect that most enterprises use either
> Exchange/MAPI or an IMAP-based solution (and of course
> Exchange also supports IMAP).

This is not the picture that I see. I think that I would have made the
same assumption you did (why bother using POP3 when your server supports
IMAP) but that's not the way it works.

In Enterprise networks using GroupWise or Notes or Exchange, a good 80%
to 100% of the clients are using the client software that pairs with the
server software. So there is a GroupWise client, a Notes client and
there used to be an Exchange client but now everyone uses Outlook. This
is the setup that the helpdesk can support.
 
Although it might appear surprising, these other 10% or 20% of users
that don't use the native client that came with the server software (for
example, a Unix machine on an Exchange server, a Macintosh on a Notes
server, or a user loosely related to the Enterprise located in the
middle of nowhere) don't use IMAP but do use POP3, and I think it has to
do mostly with IT not wanting to support fancy configurations and yes
MAPI is fancy compared to POP3. The way IT typically sees these machines
is that they are a major support pain.

From a manageability/supportability standpoint, it is not a good idea to
configure an IMAP4 client to access an Exchange server when you can have
Outlook.

There are indeed some enterprises that have a Unix-based mail system
accessed by the crowd of Windows clients; however I think these are
massively over-representated in the IETF compared to the general
population.

Michel.

---

From: "Anthony Atkielski" <[email-masked]>
Date: Wed, 4 Jun 2003 23:02:54 +0200

Michel writes:

> In Enterprise networks using GroupWise or Notes
> or Exchange, a good 80% to 100% of the clients are
> using the client software that pairs with the
> server software. So there is a GroupWise client,
> a Notes client and there used to be an Exchange
> client but now everyone uses Outlook.

True.  This is why these fancy mail systems work so well in enterprise
environments.  It's a lot more homogenous and controlled than the wide-open
Internet.

> This is the setup that the helpdesk can support.

Yes.  Some of these client programs are able to access "non-native" servers
(i.e., Exchange from a Notes client, etc., although I don't remember the
possible combinations), but it gets very ugly, very fast, and most support
organizations will not support such configurations--and neither will
vendors.

> Although it might appear surprising, these other 10%
> or 20% of users that don't use the native client that
> came with the server software (for example, a Unix machine
> on an Exchange server, a Macintosh on a Notes server, or
> a user loosely related to the Enterprise located in the
> middle of nowhere) don't use IMAP but do use POP3, and
> I think it has to do mostly with IT not wanting to support
> fancy configurations and yes MAPI is fancy compared to POP3.

Quite so.  As soon as the environment starts to get a bit mixed up,
combinations and permutations multiply alarmingly, and it becomes impossible
to reliably support anything.  Thus, whenever two disparate systems must
communicate, the safest path is the lowest common denominator ... the
simplest protocol.  So a non-Outlook client accessing an Exchange server
will do so most reliably using SMTP and POP3, not IMAP or native MAPI or
anything.

> There are indeed some enterprises that have a Unix-based
> mail system accessed by the crowd of Windows clients ...

And one of them was Microsoft itself, until it migrated to Exchange.  It's
previous worldwide corporate e-mail system used Microsoft Mail clients, but
a proprietary Xenix-based MTA, instead of the MS-DOS-based MTA that the
company actually sold to customers.  The heat that Microsoft received from
its customer base due to this obvious hypocrisy was a major motivator to
move the entire corporate user base to Exchange as soon as Exchange worked
with some degree of reliability.