What is the NativeGuid in DirectoryEntry when querying via the WinNT provider?

Question

I'm writing an application which I want to work with both Active Directory and local users and groups. I thought I could use the NativeGuid property of a DirectoryEntry as a unique identifier which was retrieved using the WinNT provider against LocalHost. However, using the following code in LinqPad I get the same NativeGuid for both entries. Querying Active Dirctory with the LDAP provider appears to yield unique results, but now I'm unsure.

System.DirectoryServices.DirectoryEntry localuserde = 
  new System.DirectoryServices.DirectoryEntry("WinNT://localhost/localuser");
localuserde.NativeGuid.Dump("localUser Guid");

System.DirectoryServices.DirectoryEntry adminde = 
new System.DirectoryServices.DirectoryEntry("WinNT://localhost/administrator");
adminde.NativeGuid.Dump("administrator Guid");

Can someone please explain what the NativeGuid represents when using the WinNT provider, and is there a good alternative for a uniqueId or is the SID a better choice?

To run the above in LinqPad hit F4 and add System.DirectoryServices.dll to the list of assemblies. Then make sure that localuser either exists or change the name to a local user on the system. Then hit F5.

Thanks,

Shane Holder

Answer 1

This other question says not to use NativeGuid. I would use the "SID" instead.

Answer 2

I would think the SID is probably your best bet in any user- and group-related scenario here. There's really no other unique identifier - especially not with the WinNT provider.

For more info on the WinNT vs. LDAP discussion and for great reference Excel sheets on what properties each of those providers really expose (and what their names are), visit Richard Mueller's Hilltop Lab. Richard is an ADSI MVP and has excellent contents for anyone interested in Active Directory and LDAP.

Marc