Take the 2-minute tour ×  I need to authenticate user's Windows
credentials, given a userId, domain and password. Our Active
Directory contains multiple domains, some which we can list
using the following code:  var domains = System.DirectoryService
s.ActiveDirectory.Forest.GetCurrentForest().Domains;  However,
we also have users that belong to domains outside the forest.
They are however accessible to me from the Global Catalog (GC).
Below code allows me to get a directory entry for a userid.
System.DirectoryServices.DirectoryEntry globalCatalogDE = new Sy
stem.DirectoryServices.DirectoryEntry("GC://DC=nsroot,DC=net");
var ds = new
System.DirectoryServices.DirectorySearcher(globalCatalogDE);
ds.Filter = "(&(objectClass=user)(sAMAccountName=" + userId +
"))"; System.DirectoryServices.DirectoryEntry userDE =
ds.FindAll()[0].GetDirectoryEntry();  How do I authenticate a
user that belongs to a domain I can not directly access but is
available to me in the GC?  share|improve this question add
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