Karl Schmidt wrote:

After much googling, it appears that one can use either exim or dovecot as the LDA - the trade offs are not clear.

It seems that the amount of mass mails all needing to get indexed at the same time would make dovecot as the LDA create a higher server peak, -- I think the inbox is only indexed in the case of exim as the LDA when users check their mail - thus spreading the load. On the other hand, I don't see where the advantage of using dovecot as the LDA is documented. It could be important for indexing, caching.

My understanding of the advantages are as follows:

1. Index updates

No other LDA knows how to update Dovecot's indices. Many people found that without their indices being updated on deliver, there was an "unacceptable" delay when opening their inbox.

2. Same config

The dovecot LDA uses the same configuration as the imap/pop servers, so they're all looking in the same places for the same mailbox types. If you changes the config, they're all in sync.

3. Options

Dovecot's LDA supports all the mailbox formats, user databases, and config sources of Dovecot. This seems obvious when you say it, but it is quite a suite of features. Just ask the next sendmail admin you see how easy it is for them to deliver to LDAP based virtual mailboxes in Maildir format...

4. Consistency

If Timo ever took on the onerous task of writing a MTA, I'd certainly give it a look in. Then my mail server could be Dovecot all the way. (Until then, I'll stick with Postfix - thanks Wietse:)

As it is, having one consistent code base and config scheme covering all your local mail handling can keep your system admin workload down.

I'm sure other people will contribute more or clearer reasons, but this is what comes to mind this Wednesday morning before my first coffee...

-- Curtis Maloney cmaloney@cardgate.net

on 6-11-2008 4:10 PM cam@ellisonpsychology.ca spake the following:

...

The correct way has to be one or the other:

http://wiki.dovecot.org/LDA/Exim

are mutually exclusive with

http://wiki.dovecot.org/HowTo/DebianStable

It appears that exim can either call dovecot's LDA or make the delivery itself. There may be good reasons to do it one way or the other.

Sorry to be diving into this issue so late, but I just noticed this email. You may be able to answer a question I have. At the moment, I use Exim and Dovecot, and have things set up to use imapd, using Dovecot as the LDA. It worked fine for a while, but with upgrades I am now unable to send email out using Thunderbird (for example - this applies to KMail and Sylpheed as well). Exim treats it as a relay, and bans it. Curiously, using these from another machine works fine. Also fine is sending mail internally, from a cron job for example, or to external addresses from my website.

It seems that the router setting in Exim is the problem, and the better solution is to use Exim as the LDA, but if one does not use Dovecot as the LDA, what's the point of having it? I installed it originally to be able to use Squirrelmail when I'm on the road. Now I'm using it all the time.

What am I missing here?

Dovecot is not just an LDA, it also serves POP3(S) and IMAP(S) services.. The benefit of using dovecot for the LDA is to keep the indexes and other files updated. I am using dovecot on CentOS, with procmail as the LDA, and everything still works fine. But you can only have one LDA ( or at least should only use one), so those docs would be mutually exclusive.

-- MailScanner is like deodorant... You hope everybody uses it, and you notice quickly if they don't!!!!