What is the User Account System (UAS)?

Paul Ashton paul at argo.demon.co.uk
Tue Apr 28 18:46:06 GMT 1998

pcc at ntsinc.com said:
> The more I look into this domain authentication, the more confused I
> become.

You're not the only one. The only way you get to understand this is
to disassemble it.

> While reading MS KB Article Q78209, I read:
>   The Netlogon service is executed to replicate the user accounts system 
>   (UAS) database between a primary domain controller (PDC), a backup domain 
>   controller (BDC), and member servers, and to validate logons to the
>   logical domain the servers are in. 


> I am assuming that the user accounts system is referring to the SAM and
> info in the NetLogon share. I am reading this to be the "domain
> syncronization of the SAM & other associated domain info" goes to the BDC's
> (which makes sense) BUT ALSO the member servers?????? Where am I going
> wrong here? Under what (if any) circumstances do memeber servers take part
> in the syncronization of a domain?

I think UAS==SAM here. I think there is a typo after BDC, I think it
should be "and for member servers, to validate logons to ...."

Take a look at the resource kit utility NLTEST. If you really want to
see what's going on with netlogon, you have to copy a checked build
version of netlogon.dll and set the DBFlags registry key. See the


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