[CentOS] Re: Mail server setup for small ISP

[Ugo Bellavance]

Ralph Angenendt wrote:
> Gary Richardson wrote:
>> It's been awhile since I looked into it, but I recommend outsourcing your
>> email.
> 
> Erks. I wonder why *anyone* in his sane mind would do so (okay, here it
> is smallish ISP but I - as a customer - trust my ISP to handle my mail
> and would get another ISP as soon as I knew that it is outsourcing mail).

Thanks for the input.  Other comments below.

>>>        For mail server, I guess I should look at an MTA and IMAP/POP
>>> server
>>> that supports LDAP and/or MySQL for users.  Postfix should be a good
>>> choice for MTA, as I know it (at least a little, but I know sendmail
>>> better).  
> 
> Then why not use sendmail? Once it is configured properly, maintaining
> users is the same as with other MTAs.

I know that it supports ldap, but does it support MySQL or another DBMS 
for addresses lookup?

>>> For IMAP/POP, I'm not sure...  Would dovecot be sufficient, or
>>> should I try cyrus.  I'd rather use components that are available for
>>> base or extras repository (or rpmforge).  I think that squirrelmail and
>>> horde would do a good job for webmail.
> 
> I've heard that dovecot scales pretty good. If you want to be on the
> safe side, cyrus probably scales way beyond what you need, but is also
> harder to maintain.

Ok, but does it scales good like in one server can handle a lot or that 
it is easy to have multiple dovecot servers serve one domain in a 
transparent manner?

>>>        There shoudn't be any troubles having some redundancy for DNS, web
>>> servers, mtas, but what about IMAP/POP?
> 
> If you're already thinking about drbd - why not share the imap store
> also?

You're right. But I'd need to have a second server ready to take the 
load if the first crashes.

> And: There still is the Cyrus Murder for bigger setups, which
> allows for flexibility within IMAP frontend and backend servers.

I wasn't aware of the existence of Cyrus Murder, I'll look it up.

> 
>>>           Or maybe IMAP proxies?
> 
> See <http://cyrusimap.web.cmu.edu/twiki/bin/view/Cyrus/CyrusCluster>
> which should answer most of your questions regarding HA within an imap
> setup.

Wow, that is great, thanks!