ISP type email system.

[WipeOut]

Hi,

I am trying to work out how to setup an email server with the following features.. (No I am not an ISP I just think that an ISP type mailserver would be the best answer.)

1. SMTP / POP3 / IMAP + SMTP TLS / POP3s / IMAP4s would be nice..
2. POP before SMTP or SMTP Auth for roaming users..
3. Per user configurable (can be increased or decreased) mailbox quota's..
4. Virtual users stored in MySQL DB (I don't want system accounts for each mailbox..
5. Webmail
6. Scaleability ( I want to be able to partition the system later if needed eg 1 or more servers for inbound SMTP, 1 or more servers for outbound SMTP and 1 or more servers for POP3/IMAP..

Starting with the MTA, I think Postfix is the best choice since it natively supports virtual users in a MySQL DB.. Onto that I was going to use Courier-IMAP which also supports user information in a MySQL DB.. but here is the problem..

Courier-IMAP only supports the maildir format.. While Postfix supports Maildir it does not support mailbox quota's on Maildir based mailboxes.. This is a problem.. There are alternate POP3/IMAP servers but they are not able to use a MySQL DB as the backend..

Also I think the theory of Maildir sounds good so I would rather use Maildir instead of the Mailbox format..

Sorry if I am getting a little technical on the requirements I would like to have..

What mail server software do the ISP's on this forum use because I am sure I am missing something here?? There must be an easy way to do this..

BTW, cost is an issue so the system needs to be free or fairly cheap..

Later..

[racksense]

Originally Posted by WipeOut

I am trying to work out how to setup an email server with the following features.. (No I am not an ISP I just think that an ISP type mailserver would be the best answer.)

1. SMTP / POP3 / IMAP + SMTP TLS / POP3s / IMAP4s would be nice..
2. POP before SMTP or SMTP Auth for roaming users..
3. Per user configurable (can be increased or decreased) mailbox quota's..
4. Virtual users stored in MySQL DB (I don't want system accounts for each mailbox..
5. Webmail
6. Scaleability ( I want to be able to partition the system later if needed eg 1 or more servers for inbound SMTP, 1 or more servers for outbound SMTP and 1 or more servers for POP3/IMAP..

All the above is quite possible to do, until you get to point 6, multiple SMTP servers should be no problem, multiple POP3/IMAP boxes becomes a challenge because you need a way of splitting the data out, or sharing it across multiple boxes, this introduces lots of complexities.

Also I think the theory of Maildir sounds good so I would rather use Maildir instead of the Mailbox format..

If you ever end up with any large mailboxes, you will certainly feel the benefit of maildir over mbox.

What mail server software do the ISP's on this forum use because I am sure I am missing something here?? There must be an easy way to do this..

We have implemented the above (minus point 6 and quotas) using all open source packages. Quota functionality should be possible to add, although there are some issues that need to be thought about..

BTW, cost is an issue so the system needs to be free or fairly cheap..

All the software is freely available, it will either cost you time to implement it, or money to get someone else to do it for you..

[illusion]

I am doing exactly what you are doing. I am also using Postfix and Courier IMAP/POP3.

It is possible to implement soft quotas in Postfix but you need an extra patch called VDA. See here:

http://web.onda.com.br/nadal/

I havent got this far yet though! I have got postfix installed and implemented the MySQL part with virtual users and its now accepting mail for those virtual users and writing to the filesystem in Maildir format.

GIve me a shout if you need any info on this.

Dan

[WipeOut]

Originally Posted by Paul-Xensia

All the above is quite possible to do, until you get to point 6, multiple SMTP servers should be no problem, multiple POP3/IMAP boxes becomes a challenge because you need a way of splitting the data out, or sharing it across multiple boxes, this introduces lots of complexities.

If you ever end up with any large mailboxes, you will certainly feel the benefit of maildir over mbox.

We have implemented the above (minus point 6 and quotas) using all open source packages. Quota functionality should be possible to add, although there are some issues that need to be thought about..

All the software is freely available, it will either cost you time to implement it, or money to get someone else to do it for you..

Glad to hear I am on the right track in terms of software but I have to ask.. If you are not enforcing mailbox quota's how do you stop your users mailboxes for just getting bigger and bigger??

[racksense]

We apply a soft limits policy - mainly because we believe that an overquota mailbox just bouncing mail is a very harsh approach to take.

We monitor mailbox usage (using a script) and warn people that they either need to reduce their usage, or buy more storage. Soon, we will be automating the over limit warning.

Part of our friendly service approach to our customers.

[jamster]

I found this link knocking around in my bookmarks if it helps
http://www.tty1.net/virtual_domains_en.html

[Cranky]

Very old thread ... but I'd say go postfix rather than exim.

[jamster]

oops yeah - definitely an old thread - hadn't noticed the date.

out of interest, why postfix?

[Cranky]

Fast, efficient, secure, well supported, well documented, easy to customise.

[racksense]

All of which apply equally to exim as well.

[Cranky]

Maybe, but I've seen better performance from postfix in the past when directly benchmarked against exim. All depends on the specific circumstances though, but my personal preference is to go postfix, then qmail (with around 600 patches to bring it up-to-date feature-wise), then exim. I've seen mailloss in exim queue on specific filesystems which don't seem to be problematic with posfix queue.

Whichever you go with though, they're fairly solid MTA's.