Would you believe we did not have to open the firewall between the resource server and the domain controller in the opposite forest?

Michael Parent MCSE MCT
Analyst I - Web Services
ITOS - Systems Enablement
Maritime Life Assurance Company
(902) 453-7300 x3456



"GRILLENMEIER,GUIDO (HP-Germany,ex1)" <[EMAIL PROTECTED]>
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yes (due to the usage of NTLM trusts).
 
BTW, I'm sure you meant single domain forests ;-)


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RE: [ActiveDir] Can someone describe teh cross-forest login proce ss?



Thanks for your response Guido!


Sorry for the sketchy detail and misnomers :-)


We are indeed speaking of Single Forest Domains running Win2K SP4. I should have more accurately used the term "authentication" as opposed to login :-)


The user will not log into a workstation in Forest B.  They will remotely access a resource from their workstation in Forest A to resource server in forest B.


So to clarify (and this is the fine point we are trying to establish), does the resource server in Forest B *directly* contact a DC in Forest A?


Michael Parent MCSE MCT
Analyst I - Web Services
ITOS - Systems Enablement
Maritime Life Assurance Company
(902) 453-7300 x3456


"GRILLENMEIER,GUIDO (HP-Germany,ex1)" <[EMAIL PROTECTED]>
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       Subject:        RE: [ActiveDir] Can someone describe teh cross-forest login proce ss?




there isn't a simple answer to this, as it depends on multiple factors

- the domain model within your forests and the trusts that you've setup between the two

- the SP level of 2000

(and it works quite a bit different once you have 2003 forests)

 

but as a start: when you are _accessing_ a resource in a trusted forest B from a worstation in forest A, this is NOT a cross-forest login process. You are merely being _authorized_ to access the resource (the authentication of your account has already happened in your forest A). Actually, for Windows 2000, we can't really speak of two _forests_ that trust each other, as 2000 can only support NTLM trusts to domains outside it's own forest (just like a trust between two NT4 domains). This means, you're not setting up a trust from forest A to forest B, instead you have to setup trusts between all domains of each forest (if the forests are both single-domain forests, then it merely looks like you're building a forest trust). Assuming single domains, we'll continue speaking of trusted forests. By forest B trusting forest A, the authenticated user from forest A is allowed to accesss those resources, where you grant the user (or a group that the user is a member of) the appropriate permissions.

 

However, as the trust between the two is built on NTLM (and not Kerberos), when the authenticated user from forest A accesses the resources in forest B, the NTLM token will be validated again against a DC from forest A (unlike Kerberos, where the token is enough to autorize access to the resource).

 
 

If the user from forest A walks up to a workstation in forest B, his authentication is naturally triggered on the workstation in forest B. This workstation follows the trust-relationship between the forest/domain it's a member of and the user is finally authenticated via a DC/GC in forest A.  So in this example, which are the GPO's that are applied to the user and the workstation??  Prior to SP4, the user's GPOs from forest/domain A are automatically applied as well as the workstation GPOs from forest/domain B.  With SP4 you can explicitely configure the GPOs in each of the domains to allow you to determine GPO processing in "cross-forest" scenarios (i.e. by default, the user GPO from forest/domain A would NOT be applied to the user logging on to a workstation in forest/domain B).

 
 

/Guido



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[ActiveDir] Can someone describe teh cross-forest login process?



I am looking for a brief synposis of the Windows 2000 cross-forest login process.
User in Forest A, accesses Resource in Forest B (one-way trust where Forest B trusts Forest A). How does the user get authenticated?


Specifically, when a resource is trying to authenticate a user from a trusted remote forest, does the authentication request only touch a local DC (presumably a GC) or does the authenticating server query a remote forest Domain Controller?


Thanks for any and all responses that shed light on this for me :-)


Michael Parent MCSE MCT
Analyst I - Web Services
ITOS - Systems Enablement
Maritime Life Assurance Company
(902) 453-7300 x3456



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