Yes it is you can use the Request.ServerVariables("LOGON_USER")
to get the NT username.
IMPORTANT:
Make sure you have Window Authentication enabled or the value will be blank. If you're using Internet Explorer to avoid being prompted make sure the site is added to the
Intranet Security Zone
.
Example:
Dim ntuser
'Will contain the NT username if using Windows Authentication
ntuser = Request.ServerVariables("LOGON_USER") & ""
If Len(ntuser) > 0 Then
'Compare ntuser against entries in database.
Else
'Must be using Anonymous Authentication check IIS settings.
End If