Performance Problems ntlm_auth <-> Active Directory under heavy load

Alan DeKok aland at
Thu Mar 19 13:42:21 CET 2015

On Mar 19, 2015, at 5:27 AM, tom greisch <tom.greisch at> wrote:
> Yesterday i have compiled Freeradius 2.2.6 and configured for ntlm_auth against an Active Directory. Everything seems ok. After testing i have redirected our WLAN Controller (with 
> thousands of Clients) to the new Radius Server and the Server was overloaded immediately. 
> (By the way our old Microsoft NPS Server had no Problem with the Load!). 

  Yes, because Microsoft NPS uses secret Microsoft APIs which aren’t available to other people.

> Until that, i decided to clone the Radius Server twice , start with "-t" Flag and set a "Freeradius Loadbalancer" bevor the "Worker Radius Server". Now i can handle the Load !

  That’s the same as setting “max threads = 2”.

  Alan DeKok.

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