Re: [MORG] POP3 LIST+ Extension: Monitoring for mailbox changes

Steffen Lehmann <> Sun, 06 February 2011 08:48 UTC

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Date: Sun, 06 Feb 2011 09:48:07 +0100
From: Steffen Lehmann <>
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To: Mark Crispin <>
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Subject: Re: [MORG] POP3 LIST+ Extension: Monitoring for mailbox changes
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Am 05.02.2011 22:29, schrieb Mark Crispin:
>> To scan through all messages of a mailbox can be a time/CPU/memory
>> consuming task for a server on big mailboxes.
> This discussion is fascinating, but it begs the question:
> If you care about such matters, why use POP3 and not IMAP?

About 80% our customers are using POP3, 20% IMAP. The decision, whether
to use POP3 or IMAP, is not ours.

> POP3 does a certain specific task, and it does that task well.  POP3 was
> never intended for any other task.

I think you have never seen a customer using POP3 tryig desperately
regain control over his mailbox when mailbox is under heavy load,
perhaps due to a mailbomb attack, or simply because the customer has
accidentally created an automatic mail responder ping-pong or a
mail-forward loop. The only remaining chance is to call the ISP and beg
for help. With POP3 - no chance.
As long as customers use POP3, for whatever reasons, we should try to
improve it, if possible.

> Each new extension (to either IMAP or POP3) creates new client/server
> incompatibility paths.  You may think that you are staying on top of
> things by implementing every extension, no matter how minimal the market
> requirement.  You learn otherwise when your customers slam you over
> interoperability problems that are fixed only by disabling the extension
> in your product.

I (carefully) agree. But this can be avoided by well-engeneered
extensions and well-tested implementations.

> I can't help but thing that MORG has devolved into a group of people
> desperate to stay on the gravy train of Building New Email Protocols,
> never mind that the train has become increasingly irrelevant.
> The more realistic only care about placing a veneer of "IETF approval" on
> a private mechanism for their client/server products.  But then there are
> the others, who live in a true Fantasy Land in which everybody will
> presently implement all 69 random extensions.
> This disease isn't confined to MORG either.  The entire IETF suffers from
> it.  I am thoroughly enjoying the IPv6 debacle as it unfolds, and look
> forward to many years of entertainment.

There is still a third group, trying honestly to improve things. Nobody
(nothing) is perfect.