Home/ Questions/Q 7820817
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-06-02T07:26:30+00:00

When we log into our Windows machines at work, we use CORP\username. Given a

  • 0

When we log into our Windows machines at work, we use “CORP\username”.

Given a user’s SID and the domain controller where they logged in, how do I derive that string? I’m using the DirectoryServices APIs added in .NET 3.5, like this:

PrincipalContext domaincontroller = new PrincipalContext(ContextType.Domain, "192.168.30.115");
UserPrincipal user = UserPrincipal.FindByIdentity(domaincontroller, IdentityType.Sid, "S-1-5-21-293182769-1777760488-2957165303-1798");

I’ve dug around the domaincontroller object and user object, and see lots of stuff like this:

user.Name:              john smith
user.DisplayName:       john smith
user.UserPrincipalName: john.smith@corp.mycompany.com
user.SamAccountName:    john.smith

If I dig deep in the private guts of the UserPrinciple object, I find two fields labelled “domainFlatName” and “FlatDomainName” which contain exactly what I want (screen shot below). What do these mean, and how I can get to them via a public interface?

Object Inspector Screenshot

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    Getting this value is unfortunately non-trivial. The attribute you want is nETBIOSName which is stored on the crossRef object representing the domain in the configuration NC.

    Given you know the DN of the domain (e.g. fabrikam.com is DC=fabrikam,DC=com), you can do a search of the configuration naming context for (&(objectClass=crossRef)(nCName=DC=fabrikam,DC=com)) and grab the nETBIOSName off of there.

    • 0