Trust types in active directory

   Communications between the domains through trusts. The trust are authentication pipelines that are must be present in order for clients in one domain to access resources in another domain. By default two trusts are created, during the active directory installation. The other four types of trust can be created using the new trust wizard or netdom cmd line tool.

Trust protocols in active directory

            The Domain controller running windows 2003 server authenticates users and application using one of the two protocols: kerberos and NTLM. The kerberos protocol is the default protocol for clients running windows 2000, XP Pro or Server 2003. The kerberos protocol, the client request a ticket from a domain controller in its domain to the server in the trusting domain., the ticket issued by an intermediary trusted by the client and the server. The client presents this trusted ticket to the server in the trusting domain for authentication.
           If a client tries too access resources on a server in another domain using NTLM authentication, the server containing the resources must contact a domain controller in the client account domain to verify the account credentials.

Active directory trust in windows 2000 and windows 2003

                    All trusts in a Windows 2000 and Windows Server 2003 forest are transitive, two-way trusts. Therefore, both domains in a trust relationship are trusted.

Trusts in Windows NT

        In windows NT 4.0 the trust are limited to two domains and the trust relationship is one-way and non-transitive.

What is mean by Trust in active directory

                       A trust is a relationship between domains that enable the users in one domain to be authenticated by a domain controller  in the other domain. the trust relationship in NT are differ than in windows 2000 and windows server 2003.