Freeradius error: "Discarding conflicting packet"

Jelle Langbroek jml at
Fri Jun 13 17:39:07 CEST 2008


Thanks for your reply. I began testing different setups immediately. I
located 1 AP which didn't regenerate the error (AP1) and swapped it with one
which did generate the error (AP2).
I then saw that AP1 (which now was located on the place of AP2), began
generating the same errors. The clients are fixed , so I tested with the
same clients on that location.
My conclusion:
1) The error probably has something to do with the WAP54G, but;
2) The error is only produced in combination with some clients (don't know
if it's a hardware issue, because it seems to have nothing to do with the
OS. OSX and Windows Vista/XP are all 'sometimes' producing the error.
3) It might have something to do with overlapping channels, but my tests are
not yet conclusive about that.

It's all so much trial and error... I decided to just buy another AP
(WAP200) to test and see if the same error pops up. I'm also going to try an
Asus WL-G330ge, just to be sure. More on that later...


ps: The models I use are Linksys WAP54G, v3.1, with firmware version 3.05.

2008/6/11 Alan DeKok <aland at>:

> jelle-e wrote:
> > Everything seems to run smoothly but before every login attempt the logs
> say
> > (something like):
> >
> > "Error: Discarding conflicting packet from client NAS-NAME port 3072 -
> ID: 3
> > due to recent request 28."
>   That's pretty definitive.
> > After that the user logs in correctly.
> >
> > I have no idea where to start searching for the answer. Since this error
> > appears to occur on every AP, I don't think they're all 'broken'.
>   It's possible.  If they're all the same manufacturer and software
> version, they could all have the same bug.
> > Does anybody have an idea? Thanks in advance!
>   Run "tcpdump" or "wireshark" to look at the packets.  Odds are the
> AP's *are* sending conflicting packets.  Look for 2 packets from the
> same client IP && port, with the same RADIUS code and ID, within a
> second of each other.  If the packet contents are different, then the AP
> is broken.
>  i.e. You can believe that FreeRADIUS is broken, but *only* on your
> system... and not on the other 10,000 systems with 100's of 1000's of
> AP's.  Or, you can believe that your AP's are broken.
>  Alan DeKok.
> -
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