Need help setting up an IMAP Server on a local network

[Bill Schmitt (SW)]

I would like to set up an IMAP server on a FreeBSD box for my home 
network. I don't have a lot of depth in this area, so could really use 
some help or pointers to "how to" pages. Searching the web and reading 
the documentation has left a couple of gaps that I would appreciate 
someone filling in. Most of what I've found seems to concentrate on 
running internet connected servers with "real" domain names on them, and 
this would sit in the local network with a separate router/firewall 
connecting the local network to a cable connection. The FreeBSD box is 
not normally visible to the outside world.

For my primary mail, I have POP and SMTP services running at the hosting 
company for my domain. The access that I have to that machine is 
restricted to pop, ftp, etc. I do not have telnet access. It appears 
that I would use something like fetchmail to get the mail from that 
server (if someone thinks there is a better tool, I'm not committed to 
it). Several of the mailboxes I have are used by people outside the home 
network, so I would leave those alone and only process a select list. I 
intend to try openxchange locally, if that impacts anything. I'd like to 
be able to retrieve mail occasionally from some other servers, like my 
ISP, though I don't use that often, so it isn't as important.

SMTP is where I start to bog down. I would like to have mail sent out 
from this central point, as well, but don't know where to start. If I 
have to configure the various email clients to send directly I will, but 
that seems like a partial solution.

I also use the FreeBSD box as a sandbox for trying things that will be 
put on a web connected server. That box has postfix and courier-IMAP 
installed, so if I could use those applications in the mix, I would like 
to, but that is not a firm requirement if someone has a good reason that 
I shouldn't. I did replace sendmail with postfix on the box a while ago, 
but haven't used it for anything.

Any suggestions, recommendations, pointers, etc. would be greatly 
appreciated.

Bill