What is difference between forest and a domain in AD?

Answer 1

The term 'domain' is too general to compare to the idea of a forest. A domain and the AD can be a part of a forest. This includes; domain controllers, child domains, domain functionality, replicators, directory service and so on. The concept of creating a forest was first introduced in the windows 2003 AD architecture. Suffice to say interoperability with server 2000 and NT (which do not recognize the forest) poses limitations and security issues. Hence four levels of functionality. Some are, in my opinion, basically unsound with regards to the security levels of a forest. A forest is not to be taken lightly. It requires much research and preparation. The term 'domain' applies across the board in a forest. Moreover, a forest relies on security. The PC you start the first installation of a forest will be considered the root and will hold the high level admins such as the enterprise and schema admins. Making forest trusts (only on root domain) facilitates communications between domains and ADs that share the same SPN (service principle name) which have to be resolved at a remote location in another forest. The configuration also requires IAS, Kerberos, UPN, SPD, SID namespaces .... What am I forgetting? Thinking about configuring the root forest on the first PC makes you dizzy with abbreviations acronyms, protocols, group security, etc ... Comprehensive research and planning are crucial. Managing forests and domain is hard enough as it is. I'd say this basic principle of security properties could be considered the largest difference between a 'forest' and a 'domain'.