Q: We want to quantify the authentication requests that are processed by each of the Windows domain controllers (DCs) in our Active Directory (AD) forest. Is there an easy way to get this information?

A: An easy way to view the authentication load on a Windows DC is to use the built-in Windows performance monitor (perfmon). Perfmon includes the following authentication-related performance counters:

  • The Kerberos Authentications/sec counter, which shows the number of times per second a client uses a Kerberos client ticket to authenticate to a DC.
  • The NTLM Authentications/sec counter, which shows the number of NT LAN Manager (NTLM) authentications serviced by a DC per second.