[Dovecot] system v. virtual mailboxes, was Re: Thunderbird problem

[/dev/rob0]

On Tue, Jun 29, 2010 at 07:28:52AM -0400, Charles Marcus wrote:
> On 2010-06-28 9:05 PM, Stan Hoeppner wrote:
> > I guess this is different with virtual users than with system 
> > users?  Are you using virtual or system users Charles?
> 
> Virtual of course... doesn't everyone? ;)

Virtual mailboxes have their place, of course, but they're overused,
especially at small sites. I suppose this might be in part because 
most HOWTOs are for virtual.

I recently saw someone asking for help, having set up a "simple" 
server with virtual mailbox (yes, singular) and mysql! The querent 
was trying to add a SECOND account and did not know how!

I started into mail on a very small scale, and that approach served 
me well. I set up Postfix by reading the comments in main.cf; later 
when I got the idea that I might want POP3 or IMAP, I uncommented 
lines in inetd.conf (popa3d I think, and uw-imap), and they worked. 
When kids got old enough to use email, adduser[1] and there they go.

I didn't get into virtual mailboxes until later, on a job, and when I 
did, I knew enough to question the wisdom of it. Why did we need this 
additional authentication database? All our users were using Samba 
via system accounts too. It could have been all integrated! The 
"advantages" I was told of doing it the virtual way were all based on 
misunderstandings. (One common one: "I don't want mail users to have 
shell access." Giving them a shell of /bin/false and/or setting 
sshd_config(5) access controls does the job.)

I think many if not most of the questions we see on these lists are 
from people who have made a bad choice of using virtual mailboxes, 
often as a direct consequence of that choice.

Email grew up with Unix, so it's no accident that Unix shell usage 
has very nice integration with email. Probably a lot of the folks 
reading this list would not even need an IMAPd if they knew more 
about these things.

I often encounter frustrated newbies who tried to do the whole thing 
all at once. It makes much more sense to start off small, throw in 
the relational databases later, learning the finer points of how to 
manage your OS along the way. The secret is that you can have a 
fully-functional mail server with very little bother, using system 
accounts. Postfix (or other MTA) and Dovecot will pretty much Just 
Work, right out of the box.



[1] adduser is a Slackware-specific frontend wrapper script for
    useradd(8) and other tools from the shadow package.
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