10.6 Server - ISP-in-box - Can it be done?

Question

I have long home-hosted a vanity domain, complete with IMAP/SMTP, web, NAT firewall, DHCP, self-hosted DNS server and the like, using the standard unix tools build into regular 10.4 machine (a 500 MHz G4 that gave 10 years of 24/7 service). Decided to graduate to a MacMini with 10.6 Server. It's not particularly easy to configure, though my ambitions may be pushing the limits.
In essence, I would like to set up a one-machine ISP/hosting service, with DNS server, standard web & email plus user-resolution file transfer/storage/permissions, and the 10.6 Apple-related bells and whistles, like home page syncing, iCal, Address Book, for the users of an arbitrary number of domains (but let's say 3). It's still mainly for me, so bandwidth and reliability are not a significant consideration - for years, I got by without configuring a secondary DNS server. And yes, I know it's cheaper and easier just to lease domains from real ISPs. I gotta server admin jones ... so kill me.
Though I can work the individual features and services (mostly) - create users, configure DNS, etc. - I'm missing some of the big picture concepts.
Is there a direct mapping between a "server" and a domain name (assuming the DNS faces out and is set up right)? Server Admin will let you create a "server", as long as the DNS resolves to a live machine (which can be itself, though it gets confused unless the domains resolve to different IP numbers, even though they are multi-homed through a single ethernet connection).
If so, can I control and configure the various services for each server/domain, independent of the others? If not, what can adding a "server" do, that a DNS entry cannot? What is the difference between a) creating a "server" having web and mail services and b) configuring virtual hosting for web and email? I realize that they'd all sharing the same kernel/applications/(maybe) libraries off the boot volume; what I want is a separate user space for each domain and associated home pages/mail/web/etc. files. Can OD handle the same user name for multiple, independent domains, resolving to their respective domain shares in the same box (in this case, partitioned on different volumes)?
I've spent a lot of time with 3 thick books, plus all the on-line docs, deciphering as much as I can. The virtual hosting info is scant. I'm not looking for a blow-by-blow (just yet), but it would be helpful to get a sense of whether this can be done at all, and if so, perhaps a sketch of the strategy - e.g., how much, and where if at all, do I need to go off the SLS GUI reservation and into the CLI?
Is this a bridge too far? Thanks to any server wizards who can shed some encouraging light.

Answer 1

You are limited to a single Open Directory - so in terms of authentication, you cannot have the same user names on the server more then once. That also means your directory administrator has access to all the users accounts - so you cannot separate account management. The Apple Admin Application does a good job for majority of the virtualisation you are seeking, e.g. mail, domain, web. What you cannot do using the Admin application, you can do by directly configuring the services themselves (but you may end up breaking the Admin). As you know, the majority of the products that apple use are open source and the web is full of information on how to configure them. You will find that whilst the Admin application is good to get you going and is does the job it is intended for, but after time, you will want to move away from it and use the more complex areas of the servers capabilities.
Other than posting questions here, good places for to get more 'internal' configuration information/help on the server are [TopicDesk|http://osx.topicdesk.com> and [afp548|www.afp548.com]