This is for a Windows environment

Your recommendation

Now i have all this runing on the same server

have more Clients coming in. need to run on Different servers

how do i do this ?

DNS - Server 1
Web - Server 2
Mail - Server 3
Sql - Server 4
FTP - Server 5

Active Directory, Domain Controller - do i need a Different Server

Need to setup in right way so if we need we can add
more servers For web, DNS, Mail, SQL, FTP

Books, web site, or Your recommendation