Client-Client communication not possible before "wpa_group_rekey"

[Dennis Borgmann]

Dear list,

I am facing problems using hostapd with two nodes, that want to 
communicate with one another. If I connect a machine to an accesspoint 
running hostapd, everything works fine, I am able to ping the 
accesspoint from the client and ping the client from the accesspoint. If 
I try to ping the clients themselves from client to client, this won't 
work, until a "wpa_group_rekey" has occurred. If I set this value within 
hostapd.conf to "60", it takes exactly one minute until I am able to 
ping one client from the other one.

The clients are ping-able from the accesspoint all of the time and the 
clients can ping the accesspoint all of the time.

Take this setup:

Laptop, Client 1
x86-machine
Atheros-WLAN
Linux 2.6.17
wpa_supplicant v0.5.5
madwifi 0.9.4.5(0.9.3)


Desktop, Client 2
x86-machine
Atheros-WLAN
Linux 2.6.19
wpa_supplicant v0.5.7
madwifi 0.9.4.5(svn r1865)


Accesspoint, running hostapd v0.5.10 (tested as well with 0.6.3)
PPC-machine
Atheros-WLAN
Linux 2.6.23.1
madwifi 0.9.4


All of these machines are connected via wireless-LAN, the configfiles 
for hostapd and wpa_supplicant are as follows:

hostapd.conf

interface=ath0
driver=madwifi
bridge=bridge1
logger_syslog=-1
logger_syslog_level=0
logger_stdout=0
logger_stdout_level=0
debug=2
dump_file=/tmp/hostapd.dump
ctrl_interface=/var/run/hostapd
ctrl_interface_group=0
ssid=Embi Netnode 0
channel=1
auth_algs=1
ap_max_inactivity=300
wpa=1
wpa_passphrase=embigence
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
wpa_group_rekey=3600



wpa_supplicant.conf (on both client-machines):

ctrl_interface=/var/run/wpa_supplicant
ap_scan=1
network={
   ssid="test_ssid"
       scan_ssid=1
    proto=RSN WPA
   key_mgmt=WPA-PSK
       pairwise=CCMP TKIP
       priority=2
   psk="test123"
}

Any ideas, what might be my problem? any help would be appreciated.

Thanks in advance, Dennis