radutmp file problem with simultanous problem

Alan Dekok aland at deployingradius.com
Mon Apr 2 12:16:14 CEST 2007

satish patel wrote:
>                   I have very strange problem i am useing freeradius 
> with mssql database and it is working fine since 1 month without error 
> but last week my radius server power switch off or due to any power 
> reson my radius machine would shutdown now when it come back i run 
> radwtmp there is list of users and when i goes or telnet on cisco NAS 
> there is no one users

   Yes.  FreeRADIUS only knows what the NAS sends it.  If the NAS never 
tells FreeRADIUS that it rebooted, the server has no way of knowing that 
there are no users still on the NAS.

> and after it i check radius log i saw the max 1 
> login error means multiple users login problem so what is the problem i 
> know the problem but this is not a way caz it caz happend any time then 
> i delete /var/log/radius/radutmp file

   "man radzap".

> then again users able to login 
> this is the simultaneous login problem i know caz checkrad first check 
> radutmp and then check in to NAS i know logic behind this but this is 
> not a proper solution then how can i resolve it is there any method to 
> adovide this problem..

   checkrad *should* work if you have configured it.  And it doesn't 
work the way you think.

   If "radutmp" says that the user isn't logged in, he is allowed in.

   Otherwise, "checkrad" is run to ask the NAS if the user is logged in.

   If the user isn't logged in, then the entry in "radutmp" is deleted, 
and the user is allowed in.

   Alan DeKok.
   http://deployingradius.com       - The web site of the book
   http://deployingradius.com/blog/ - The blog

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