checksimul callback

Dmitry V. Krivenok krivenok at
Thu Oct 16 17:44:39 CEST 2008

Alan DeKok wrote:
> Dmitry V. Krivenok wrote:
>> What is the purpose of checksimul callback?
>  Checking Simultaneous-Use.
>> When is it called?
>   When Simultaneous-Use is set.
>   If your module doesn't implement user accounting, don't implement this
> function.
I'm newbie here.
I haven't learned all capabilities of freeradius yet.
I just want to know what is the simplest way to
disallow 2 simultaneous sessions.
Are there any standard solutions?

I found (in source of rlm_sql), that checking is based on
analysis of accounting information.

What if 2 Access-Requests arrive "simultaneously"?
There is no accounting information available yet (it will
become available just after receiving Accounting-Start).
Hence it's not reliable to rely on accounting information only.
Am I right?

It seems to me that AAA and NAS may be not synchronized.
So, we need to contact NAS somehow to determine active
sessions and match them with accounting info.
Looks like very complex task :(

>   Alan DeKok.

Sincerely yours, Dmitry V. Krivenok
Orange System Company
Saint-Petersburg, Russia
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