error discarding packet
b.dimitrov at ngsystems.net
Wed Dec 23 14:28:47 CET 2009
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
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".
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.
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.
1) Check the ML for more info
2) The NAS can be configured when to timeout and resend the RADIUS
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.
e-mail: b.dimitrov at ngsystems.net
GSM: 0888 51 55 45; 0889 28 54 57
Lavele 32 str, fl: 4,
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
> but, i'm still having this problem
> and I dont know what can be
> Alisson F. Gonçalves
> Sistemas de Informação - UFGD
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