error discarding packet

[Borislav Dimitrov]

Hi,

This question has been answered many times on this ML. I myself have  
(at least tried) answered it two times. Here're some of my previous  
messages:

Msg1:
Hi,

I've already tried to answer a similar question some time ago (and I'm  
probably not the only one) but anyways...
The cause of the problems probably is some delay or packet loss or  
something like that. Notice the Acct-Delay-Time value increasing as  
the NAS retries to send the "lost" accounting packet (although - at  
least in my case - it wasn't lost but just its processing was  
delayed). I've experienced such issues with Cisco VoIP routers - the  
router's log is flooded with RADIUS Server DEAD - and then ... ALIVE  
messages and in the FR log you can see the retries with the values of  
Acct-Delay-Time increasing. The main cause of the problem may be  
different, so you'll have to check it in your case. In my case it was  
caused by the thread pool settings not being appropriate for the load.  
In this case the CPU usage stays low but it's not used because you  
cannot achieve good concurrency and request have to await each other  
to finish. So find the main cause for your problems and eliminate it.  
The other thing is that most NASs have options to configure the RADIUS  
timeout, dead, retransmit etc times. E.g.for Cisco you could try  
"radius-server retransmit 0".

Msg2:
Hi,

As far as I can see, the people on the list have provided you with a  
lot of very useful suggestions on what could cause the problem. As I  
said earlier (let me clarify) and to help you narrow things a little  
bit - it's probably due to the RADIUS response timing out hence the  
NAS complains the server is dead and later when it responds finally it  
marks it as alive again. The reasons can be different depending on  
your setup - slow network, database, custom module (like rlm_perl/ 
python etc) or as I suggested (from my personal experiences)  
improperly configured concurrence settings of FR itself. See which  
component of your setup is causing the slow responds (it can be the  
backend, or messed up FR configuration) and fix it. Just for  
completeness check your NASs manuals - most have these settings  
configurable - response timeouts, retransmits, marking the server as  
dead etc but playing with the NAS while possibly useful is probably  
not the main issue in your setup - check what is slowing things down.

Msg3:
Hi there,

I may be mistaken but... these are log message on the NAS aren't they?
If this is the case, I've experienced similar behavior with Cisco VoIP  
routers (RADIUS Server DEAD and then... ALIVE). This happens if you  
haven't properly enabled concurrency in FreeRADIUS - the CPU usage  
stays low 0%-1%-2% but if the requests are many they are obviously  
waiting each other... This happens when you have stared FreeRADIUS  
with the -X key (I think it starts with a single thread then) or have  
too low values for the thread pool parameters (and/or the *_clones  
options of rlm_perl which are to be deprecated soon). If you configure  
proper values according to the expected usage (concurrent requests),  
then the request won't wait each other to finish while the CPU stays  
unused and you'll avoid this annoying message in your logs. A sure  
sing that something like that is going on is the Acct-Delay-Time  
parameter with values greater than 0 - that is for accounting not sure  
for auth etc. Anyways if the values of that parameter are high (they  
are in seconds I think) then the requests are waiting too long and  
hence the error messages.

Bottom line:
1) Check the ML for more info
2) The NAS can be configured when to timeout and resend the RADIUS  
packages
3) Something is slowing down your setup. It may be the DB or something  
else. If your CPU usage stays low (< 5%), check your thread pool  
settings and increase them to achieve better concurrency.

Sincerely,

Borislav Dimitrov
e-mail: b.dimitrov at ngsystems.net
GSM: 0888 51 55 45; 0889 28 54 57
NG Systems
Lavele 32 str, fl: 4,
Sofia, Bulgaria



On 23.12.2009, at 15:10, Alisson wrote:

> hi, in another day I posted this same error ' Error: Discarding  
> duplicate request from client '
>
> and the answer was 'your database is slow'
>
> so I upgrade my server with more memory, and changed servers  
> variables...
>
> but, i'm still having this problem
>
> and I dont know what can be
>
> -- 
> Att.
> Alisson F. Gonçalves
> Sistemas de Informação - UFGD
> -
> List info/subscribe/unsubscribe? See http://www.freeradius.org/list/users.html