[Dovecot] LMTP revisited

[Jakob Hirsch]

Quoting Glenn Leavell:

> I think I'm probably showing my ignorance here:  My understanding is that
> Dovecot's LDA gets called once per recipient, so that it wouldn't know
> whether any given message is a duplicate.  Or is the idea that Dovecot's

That's the common way to use LDAs.
On many systems, mailboxes belong to seperate users, so for delivering
into multiple mailboxes, a LDA would need to have root rights, either by
being called from a root process (at least Postfix and Exim will not do
that) or be SUID root. Procmail is said to be able to do
multi-deliveries this way, but it's an ugly piece of software.

> LDA would be able to easily detect duplicates based on its own index
> information?

That would be unnecessarily cumbersome.

>> The one thing that disturbs me with this kind of hardlinking is that
>> then there are no Delivered-To headers (and others?) which are normally
>> added to mails.
> Yes, I guess we'd have to take that into account when deciding whether to
> use single instance storage.

Are they necessary for anything special? Exim does not set this header
(unless specially configured to do so), its default header is
Envelope-to, which contains the list of envelope recipients.

Anyway, if you have so many large messages going to multiple recipients,
couldn't these people be put into groups and use shared mailboxes?