YES!! it can be a win domain controller, you need a program called samba server. it allows a linux pc to not only host shares viewable to windows machines, but to be a domain controller, serving up roaming user profiles etc.... this took me about a year to find out. it is quite an extensive thing to set up, but it works. I know this because i was bored one day, so i set up a domain with a server and 1 client
. It was a while back, so i cant remember much, but i think you have to set the server to user mode, as opposed to share mode etc. btw, domain mode, is NOT what you need to use,this is for connecting to domains, dont get confused with this. and DONT use the GUI of samba for this, it doesn't allow you to do what you need to.
one last note: if you get problems on ur windows clients about not being able to access the profile, it is 90% of the time due to permissions on the server being set incorrectly(ie, disallowing access to the profile folder).
sorry, but i dont know much about DNS.
hope this helped.