Empty (not ended) session - freeradius 3.0.16

Winfield, Alister Alister.Winfield at sky.uk
Mon Apr 9 17:41:20 CEST 2018

As Alan says you should use the Accounting On to stop all active sessions from a NAS.

There is, however, also the case that you somehow miss all attempts to send the STOP for a session. This is similar and no amount of people think it'll be impossible to happen. Yep it does and you have to handle it. Normally, I'd always enable interim accounting and any session that’s not had any accounting for say 2 interims is marked as 'dead' (note distinct from STOPPED to show its heuristically closed rather than absolute fact). Also rather obviously any START that has the same IP as an existing session should close the old one before STARTing a new one...

I could go on listing the cases but after realising that RADIUS packets aren’t guaranteed to arrive, and other than infinite retries you can't guarantee it 100% you will get stale sessions and your RADIUS accounting system has to do the right thing when it happens.


On 26/03/2018, 21:07, "Freeradius-Users on behalf of dg" <freeradius-users-bounces+alister.winfield=sky.uk at lists.freeradius.org on behalf of dg at poczta.tarman.pl> wrote:


    i have another question about not ended sessions in FR (thanks Alan for last

    What about situation when switch is suddenly down (for example power failure).
    and empty sessions appears in database.

    in this case NAS wont send stop packets (because of suddenly power failure).

    Can i avoid this ? i mean empty session (with stop time -> NULL).
    Is there any way that FR will check if NAS or end user is still alive ?

    best regards

    On Feb 27, 2018, at 5:34 AM, dg <dg at poczta.tarman.pl> wrote:
    > From time to time I have session not ended (and without any user assigned to
    > that session).
    > So i have time when session starts but stop time is NULL.

      The NAS isn't sending stop packets.  FreeRADIUS can only log what it gets.

    > so you can see that AcctStopTime is sometimes NULL.
    > Can someone help me ? why its happening ?
    > i am using cisco switches

      Fix the switches to send stop packets.

      Alan DeKok.

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