I'm tryign to establish a transitive Trust between two forest but it only ceatenon-transitive trust. How do I do that?

More than likely you are not on a supported Forest Function level. Creating Forest Trusts: http://technet.microsoft.com/en-us/library/cc776940(WS.10).aspxVisit: anITKB.com, an IT Knowledge Base.

Forest Trusts by definition are the equivalent of creating transitive trusts between every domain in each forest. Read this for more information. http://technet.microsoft.com/en-us/library/cc773010(WS.10).aspx As far as i know, Forest Trusts themselves are not Transitive meaning Forests trusts betwen three forests (A->B->C) are not transitive. Thus A trusts B (->) but not C, because they are not transitive. Since you only have 2 Forests this doesn't apply anyway.

It's hard to say the cause as you need to provide some environment detials on what OS you're using. Nontransitive trust A nontransitive trust is restricted by the two domains in the trust relationship. It does not flow to any other domains in the forest. A nontransitive trust can be a two-way trust or a one-way trust. Nontransitive trusts are one-way by default, although you can also create a two-way relationship by creating two one-way trusts. In summary, nontransitive domain trusts are the only form of trust relationship that is possible between the following: A Windows Server 2008 or a Windows Server 2008 R2 domain and a Windows NT domain A Windows Server 2008 or a Windows Server 2008 R2 domain in one forest and a domain in another forest (when the forests are not joined by a forest trust) AD Forest level transitive trusts aren't allowed (Forest A trusts Forest B & Forest B trusts Forest C, but Forest A & C trust isn't transitive as a result.) Forest trust: A transitive trust between a forest root domain and a second forest root domain. much of this is related that forests are the formal security boundary. http://technet.microsoft.com/en-us/library/cc773178(WS.10).aspx http://technet.microsoft.com/en-us/library/cc754612.aspx

i'm runing Win2003 R2 and it has 2-way non-transitive trust relationship.The problem is that i can't login acorss the to domain but at the same time i can access the files. This what non-transitive designed for. The documentation says I've make some DNS changes which I'm reluctant to do in the live/production environment unless i'm not sure.

"If there is no shared root DNS server and the root DNS servers for each forest DNS namespace are running a member of the Windows Server 2003 family, configure DNS conditional forwarders in each DNS namespace to route queries for names in the other namespace. " since both the Forest has their own DNS server, do i need to create the condition fwding on both of these. let say domain A ea.local and domain b is ns.local , then what do i need to do in DNS?

I've setup the forwarder and I can Ping the computer across both the forest. what else?

Read up on the basic implentation for domain trusts. http://technet.microsoft.com/en-us/library/cc776940(WS.10).aspx