Email server control panel

[Steve Buehler]

	I was hoping somebody here might have a solution for my problem.  I 
am wanting to setup an email server for our clients.  So they would 
have one server for their websites and one server for their 
email.  The following is the minimum of what I need for it.

1.  Control Panel for each domain so that the domain owner can add 
their own email addresses.
2.  Control Panel for each user that is added to a domain so that 
they can change their own passwords if they want.  Also so that there 
can be a link to a program like Squirrelmail that we would install on 
the server.  I only want one copy of Squirrelmail if possible so that 
copies don't have to be installed for each domain.  The program 
Squirrelmail can be another program, but it would be nice if it was 
Squirrelmail because I know and like it.
3.  Control Panel for the main Admin to add the domains that will be 
on the server.
4.  Virtualization so that each domain can have an "admin" or "steve" 
if they want as their logins.
5.  Must run on a RHEL ES 4 or 3 server.
6.  MailScanner/SpamAssassin with a virus scanner.  For a normal 
installation of a server, I can install these with no problem.  It 
doesn't have to be MailScanner/SpamAssassin if there is something 
else that would work just as well and is as easy to manage/learn.  A 
virus scanner for all incoming and outgoing email is a must and no 
solution will work if it can't do this.

My main problem is that the solutions that I find won't fit the bill 
because of one or more of the following:
1.  Can't install the program, Control Panel, on our own server.
2.  Cost to much
3.  Has a monthly charge to use it
4.  Want a per domain charge, which would again...cost to much since 
we have about 1000 domains.
5.  Won't work as just an email server.  It wants to be the whole 
hosting solution and at the moment, we don't want that and can't 
change the Ensim control panels that we have now.  We are going to 
stick with the Ensim control panel for the web hosting but need to 
move the email off to a separate server because of the load on the 
server due to 10's of thousands of emails that our clients get and 
receive daily.

A free solution would be the best option if available since the 
majority (about 95%) of our clients are low end and don't pay much 
more than $20US a month.  VPOPmail 
http://www.inter7.com/index.php?page=vpopmail is a nice solution, but 
it only runs on qmail and, if possible, I would rather use sendmail.

Thank You
Steve