problems with EN2511CD / NL2511CD

Jouni Malinen jkmaline
Sun Jan 12 21:06:25 PST 2003

On Sat, Dec 21, 2002 at 07:28:02PM -0800, dean gaudet wrote:

> the attached file was collected by "tethereal -s 1600"... i hope it helps!

> > > On Mon, Dec 02, 2002 at 10:59:24PM -0800, dean gaudet wrote:
> > > > Dec  2 22:46:51 mewlark kernel: wlan0: 00:40:96:5a:5d:ce auth (alg=0 trans#=1 stat=0 len=6 fc=00b0) ==> 0 (authOK)
> > > > Dec  2 22:46:51 mewlark kernel: wlan0: 00:40:96:5a:5d:ce auth_cb - frame was not ACKed

The capture log seemed to miss lot of messages. There was only one
beacon frame although there should have been about 10 beacons a second.
In addition, more or less all ACKs were missing. If these frames were
really missing, it would explain problems. However, I do not know why
the station even tried to authenticate with the AP. It was sending Probe
Requests for SSID 'groove kitchen' (i.e., not wildcard accepting any
SSID) and the AP was (based on that one beacon frame) configured to use
SSID 'test'. AP did not reply to probe requests because of this.

Based on the numerous retries of authentication messages it looks like
there are some problems in packet acknowledging. The packet dump did not
show ACKs, so this might have been due to some problems in capturing the
frames or AP (and actually even station) not ACKing them.

I cannot determine cause for the main problem based on that packet dump.
I would try making sure that the client station is configured to use the
same SSID as the AP. It might be possible that the wlan card in AP does
not ACK all frames for unknown reason. I have seen this happening with
Prism2 cards, but usually in station mode. I do not know what is the
real reason for this. Sometimes it is enough to reset the card ('iwpriv
wlan0 reset 0' or 'iwpriv wlan0 reset 1') to get ACKing back; sometimes
this is not enough..

Jouni Malinen                                            PGP id EFC895FA

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