Jouni Malinen j at w1.fi
Sun Apr 7 07:02:24 PDT 2019

On Sun, Mar 31, 2019 at 06:53:29PM -0700, Nils Nieuwejaar wrote:
> I'm trying to debug an EAP hostapd problem.  I'm using one hostapd instance
> to act as a wireless AP, and a second hostapd instance on the same box as a
> Radius server.  Both instances are running hostapd 2.7.
> I frequently enter a state where a client is attempting to authenticate, but
> gets stuck in an endless loop of CTRL-EVENT-EAP-RETRANSMIT events.  Eventually
> the client gives up, disconnects, reconnects and enters the loop again.  If I
> kill the AP hostapd process and restart it with the same config file, the client
> will be able to connect.

> Below is a merged hostapd/radius log showing the failure.  We can see that the
> two hostapd instances are successfully communicating with one another
> throughout.  We can also see that some clients are able to connect even while
> one is stuck.  We also see that the troubled client is able to connect as soon
> as hostapd is restarted.  All of this implies that the problem is with some
> state about this client, either inside hostapd or the wireless driver, which
> gets cleared when hostapd restarts.

Or in the station device that has connectivity issues.. Stopping and
restarting hostapd ends up sending a broadcast deauthentication notice
that may clear such state.

> Does this sound familiar?  Any suggestions for next steps?

I'd take a look at more detailed hostapd debug log from the AP (stdout
from hostapd with -ddt on command line) and ideally also a wireless
sniffer capture showing what frames are exchanged between the AP and the
station that has problems connecting.

Jouni Malinen                                            PGP id EFC895FA

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