Proxy Server Deployment - Duplication of Radacct entries in the DB

[Gabriel Marais]

Hi Guys,

I need some advice on setting up Proxies (correctly).

Currently, I have two freeRadius servers in the EU and two proxies in
Africa. The proxies are configured in a fail-over scenario pointing to
the two freeRadius servers in the EU.

We receive accounting packets from an upstream carrier which has a
fail-over, and in some cases have a load-balance configuration on
their side pointing to our proxies.

Our proxies receive those packets and they are forwarded to the radius
servers in the EU where all the "processing" takes place. The radius
servers in the EU are connected to a MySQL cluster where we make use
of accounting information for session and capping purposes.

The problem now, as far as I can ascertain, is the duplication of
sessions in some cases for the same "user name" and as far as I can
tell this happens when a proxy server sends the accounting start
packet to radius server 1 in the EU - the radius server adds the
information to the DB with an unique accounting session id. When the
interim update is received by the proxies and that interim update
packet is sent to radius server 2 in the EU, the server then creates a
new radacct entry in the DB with a new unique accounting id since it
cannot find an existing session in the DB with the unique accounting
id created by the radius server that first received the start packet.

Is there some specific way I need to modify my queries.conf files on
the radius servers in the EU or some specific way I need to configure
my proxies for them to better handle cases like this? My queries.conf
file is the standard out-the-box config apart from adding some
relevant 3GPP values to be written on accounting start and interim
update packets into the DB as received from the carrier.

Thanks in advance.

Regards, Gabriel