On Mon, 21 Dec 2009 13:44:42 +0100 Joan <aseques@gmail.com> wrote:

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You need to check user's quota on routing stage, not transport.

It'd be much better, because I would allow me to mix overquota and no-overquota recipients. But the problem in my case is that I am using some hashing to distribute the users' mailboxes, dovecot can handle this easily because it supports some interesting stuff (http://wiki.dovecot.org/Variables)

Exim have much more variables and functions http://exim.org/exim-html-4.69/doc/html/spec_html/ch11.html#SECTexpvar, so if you don't use any special dovecot variable data, than it shouldn't be a problem.

With a perl script I could also do that, I would like only if it's the last resort (too much overhead I would think)

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Parsing file and counting quota value - is trivial stuff. The main disadvantage of this way is executing external aplication on every RCPT TO command. If you'll decide to use perl consider using option perl_at_start to minimize aplication starting time.