Problem - Duplicating IPs

Rui Ribeiro ruyrybeyro at
Tue Feb 17 05:42:44 CET 2015

Hi Alan,

Forgive my ignorance, but are you implying DHCP is keeping up with
accounting data?

 I tried to write a script to identify users via a web page to give some
accounting stats and quickly reached the conclusion it was not real time
(i.e. if done immediately upon login it would often show the previous
user). When in Meru training they also confirmed me the delay when
receiving accounting data could be up to 3 minutes for their equipment, if
I am not wrong, giving the delay from the top of my head.

So the idea I have is whilst accounting is very useful, it is not exactly
real-time, correct?


> Message: 4
> Date: Mon, 16 Feb 2015 08:44:22 -0500
> From: Alan DeKok <aland at>
> To: FreeRadius users mailing list
>         <freeradius-users at>
> Subject: Re: Problem - Duplicating IPs
> Message-ID: <067378F3-DD2D-4CAE-9CAE-9CD20275DACD at>
> Content-Type: text/plain; charset=windows-1252
> On Feb 16, 2015, at 7:37 AM, Marcelo Santoro < at>
> wrote:
> > I am facing a problem here in my ISP.
> >
> > I have radippool configured in my freeradius 3.0.6 server and some times
> my customers are receiving Duplicated IP address,
>   Fix your NAS so that it sends the correct accounting packets.
>   FreeRADIUS *assumes* that the accounting information in SQL is correct.
> If the NAS doesn’t behave properly, the data in SQL will be wrong.  And the
> server will assign duplicate IPs.
>   Until you get a real NAS (or fix your current one), the best solution
> would be to write a script to read IPs from SQL, and then scan those in the
> network.  If there’s a response, update SQL to mark the IPs as still in use.
>   Alan DeKok.


Rui Ribeiro
Senior Sysadm

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