Informations about home_server_pool with load-balancing or fail-over

Geaaru geaaru at
Sun Jul 26 23:21:33 CEST 2015

Hereinafter my comments. Thanks again for reply.

I also add another question...

7) Is there a variable to use on detail log to identify Ip address of
home_server used (from a pool) for example on a load-balancing proxy
scenario ?

Ah, fyi... I see that on freeradius site homepage link to unlang keywords
are broken for version 3.0.9 (available path is for version 3.0.8).

2015-07-25 14:12 GMT+02:00 Alan DeKok <aland at>:

> On Jul 24, 2015, at 7:56 PM, Geaaru <geaaru at> wrote:
> > I see freeradius documentation but I have some doubt about how
> > load-balancing/fail-over it works when is enable status-server or not.
> >
> > 1) From documentation I see that an home_server_pool with load-balancing
> > split requests between all home server. But FWIK or I understand if
> request
> > doesn't receive a response from first home_server is not send to second
> > like for fail-over. Is this correct ?
>   No.
>   The proxy fails over when:
> a) the home server is marked dead, and then
> b) the NAS sends another packet.
>   If the NAS doesn't send another packet, the proxy will not be able to
> fail over *for that packet* to another home server.  The *next packet* will
> see that the home server is down, and the proxy will choose another home
> server

Ok. While with fail-over type on proxy failure sequence is:

a) the home server is  marked dead

b) proxy send packet to second home server with status alive/unknow without
wait for a re-transmission from NAS.

Is correct ?

> > 3) About status-server check... In my configuration I set status_server
> to
> > yes under security section but If I haven't enable site status (on port
> > 18121 for example) I can receive however Status-Server request only on
> port
> > 1812 and 1813. Is this correct?
>   Yes.
> > 4) home_server gone on alive status only if at least one request is been
> > received from server else home_server is leave on "unknown" status. Is
> this
> > correct ?
>   Yes.  "Unknown" is equivalent to "alive".  The only difference is that
> it's a bit more information for the administrator.
> > 5) Is there a way to set alive status of all home_server automatically at
> > bootstrap ?
>   No.
> > I see that with fail-over if I haven't received request from
> > startup (status of home_server is unknown) then on a failure of first
> > home_server, request is not sent to second home_server (at least on 3.0.8
> > version). Instead, if I have both home_server in alive status and I power
> > off first home_server, than request is correctly sent to second on
> failure
> > of first.
>   It's more complicated than that.  The NAS has to retransmit.
>   Use radclient, with "-r 20", so it sends 20 retransmits.  You WILL see
> the proxy fail over from one home server to another.

But why if all home_server are in status alive (and first failure on
receive packet) proxy send directly to second home_server without

RFC how describe fail-over operation ? Can you said me what are RFC that
describe these operations ? Thanks.

> > 6) If I haven't active status-server is there a way to handle home_server
> > only alive to avoid zombie period if a request go to failure / timeout ?
>   I don't know what that means.

Yes I don't understand what I wrote. This happens when I write email to
night. :)

A client said me that 3GPP specification doesn't expect a response about a
Disconnect-Request if session doesn't exists or is already down. Do you
know if this is correct ?

>From freeradius side this means that when I receive a Disconnect-Request to
an already closed session and proxy forward correctly packet to correct NAS
, proxy doesn't receive Disconnect-Nack or Disconnect-Ack and so NAS is
marked as zombie/dead.

Is there a way to leave status alive for this case ? For example handle
Failure and said through unlang language to ignore timeout on reply of the

NAS doesn't support status-server extensions so I can't enable

>   Alan DeKok.
> -
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