Dovecot and domain quotas

Wed, 20 Oct 2021 23:36:14 +0200

hans@social.woefdram.nl

Do I have any #Dovecot experts among my followers? I'm trying to setup Dovecot so that I can assign #quotas to both individual users and entire domains. The individual quotas are working, that's fairly well documented and there are many example configurations to be found online that can provide inspiration.

Domain quotas are different though. I know I'm pretty bad at searching (well, searching is ok, but finding isn't my strongest point), but it seems like nobody does domain quotas the way I want to. I want to be able to assign a quota to a domain and leave all users within that domain without quota, so that everyone can keep receiving mail until the domain quota is reached.

I'm using a dictionary in MySQL to keep track of individual user quotas, and my SMTP-servers can check quotas in realtime so they can decide whether to accept or reject an incoming message for that user. I want my domainquota information in a MySQL dictionary too, which would be flexible enough to add a couple of extra Dovecot servers when I have to scale up.

computers

show all 21 comments

Wed, 20 Oct 2021 23:41:33 +0200

You are bad at searching :-)

https://serverstutorial.wordpress.com/2012/12/28/configuring-domain-user-mailbox-quotas-in-dovecot-via-postfixadmin-on-ubuntu-12-04lts/

Wed, 20 Oct 2021 23:42:02 +0200

But be aware, it is on Ubuntu :-)

Wed, 20 Oct 2021 23:50:00 +0200 last edited: Wed, 20 Oct 2021 23:50:14 +0200

Hans van Zijst

hans@social.woefdram.nl

That is one of the articles I used for inspiration, but either it's outdated (a lot can happen in 9 years) or there are errors in it: it didn't do the trick.

maxquota in the domain table – this is the domain quota limit stored.

That's not true, at least not anymore. That field is used to indicate the maximum quota for a user in that domain.

Wed, 20 Oct 2021 23:52:15 +0200

Well, I am sure that Dovecot itself might have manuals, or even postfix. Ask mr. Venema :)

Wed, 20 Oct 2021 23:56:03 +0200

Hans van Zijst

hans@social.woefdram.nl

The Dovecot documentation is not that elaborate, unfortunately. One of the things I found was:

The dict key must match exactly priv/quota/storage. The dict keys are hardcoded in the Dovecot code, so depending on what functionality you’re configuring you need to know the available dict keys used it.

I looked at the source code, but that didn't yield anything. I'm not exactly a programmer, my last C efforts are well over 20 years ago.

Wietse Venema is Postfix, this is Dovecot ;-)

Venema does answer questions to the Postfix-mailinglist btw, very nice to see.

Wed, 20 Oct 2021 23:58:26 +0200

I know, talked to him when I hacked Plone. Nice guy and responsive. He might be able to point you to a good manual

Thu, 21 Oct 2021 00:04:04 +0200

B.t.w., I do know a very dirty hack :-) Enable os quotas per domain (directories). But again, that is very ugly. I once used it some 25 years ago (I think)

Thu, 21 Oct 2021 00:04:13 +0200

Hans van Zijst

hans@social.woefdram.nl

I've sent a message to the Dovecot mailinglist, let's hope someone replies with a couple of leads. I don't see Wietse's name there, at least not since I subscribed three years ago.

Thu, 21 Oct 2021 00:04:50 +0200

And if all is stored in Mysql you can partition it

Thu, 21 Oct 2021 00:06:08 +0200

Hans van Zijst

hans@social.woefdram.nl

Hmm, I'm not looking for a dirty trick here. That would be fine for a private machine with a handful of users, but this one is production and should host hundreds of users within the next few months. Can't afford to use quick-n-dirty stuff there, this has to be solid.

Thu, 21 Oct 2021 00:09:54 +0200

Hans van Zijst

hans@social.woefdram.nl

I used a trick like that on my own server a few years ago: filesystem quota. It works, technically, but Dovecot isn't aware of any quotas so users aren't either. And it was OK for me to configure quotas manually for the few accounts I host on my private server, but that's no viable solution for a platform where you want your clients to do most of their administration themselves.

Thu, 21 Oct 2021 00:12:17 +0200

That is why I mentioned a dirty Hack :-)

Thu, 21 Oct 2021 14:22:23 +0200

Hans van Zijst

hans@social.woefdram.nl

Still no reaction from the Dovecot mailinglist :-(

As with missing persons: the first 24 hours are critical...

Thu, 21 Oct 2021 14:24:53 +0200

Ask Wietse, he might know.

Thu, 21 Oct 2021 14:25:18 +0200

Or, if you happen to know him, Hans Spaans

Thu, 21 Oct 2021 17:24:01 +0200

Hans van Zijst

hans@social.woefdram.nl

This doesn't look good:

https://osomdev.pl/blog/2020/04/06/is-it-possible-to-configure-per-domain-quota-in-dovecot/

That's just one year ago...

Thu, 21 Oct 2021 18:59:42 +0200

To be honest I see no real reason why it shouldn't work correctly, this is only a statement.

https://doc.dovecot.org/configuration_manual/quota/

Are you using mysql for it too?

Thu, 21 Oct 2021 19:07:47 +0200

Hans van Zijst

hans@social.woefdram.nl

Try it ;-)

It just gets the quota for the first user in the domain.

Thu, 21 Oct 2021 19:11:15 +0200

Then you need to simply find an alternative. But did you set it up as stated in the wiki? Or did you simply read the blog and came to the conclusion it does not work?

Thu, 21 Oct 2021 19:19:02 +0200

https://workaround.org/ispmail/buster/quotas/

Some seem to be able to get it working :-)

Thu, 21 Oct 2021 21:47:58 +0200

Hans van Zijst

hans@social.woefdram.nl

@Hans Wolters That's the user quotas, I got all of that working like a charm. What I want in addition to that, is quotas per domain.

What I read in several articles, is that this is either "tricky" or not possible. So I'm going to take a different route here and see if I can fix it with a combination of filesystem quotas and the appropriate Dovecot plugin for that.