problem with iPhone and Samsung mobiles

Tamas Selmeci tselmeci at dension.com
Wed Feb 18 07:41:14 EST 2009


Hello all!

I'm new to this list but not new to hostapd. This AP program has been 
used by me several months for creating our very own AP on an Intel 
XScale-based platform. And it works usually perfectly. As we use Atheros 
wifi cards, the previous wifi driver was madwifi, but since then we've 
switched to Atheros n cards, so ath9k is being used.

90% of the devices tested with hostapd works perfectly: they are capable 
of connecting to the AP, they get an IP (udhcpd) and are able to 
communicate. One of the functions of the device I'm developing is to act 
as a hotspot; these mentioned devices can surf the net though the hotspot.

But there are problems: two mobile phones fail to surf the net. These 
phones are Samsung i780 and Apple iPhone.

The situation in detail: they connect to the AP, authentication and 
association succeed, they get an IP address from the DHCP server. Problems:
- when they get pinged from another host on the AP, or even from the 
computer running hostapd, only the very first ping has a reply (but not 
necessarily, sometime this fails too), further pings fail;
- telnet, ping and other tools were installed on the Samsung (Windows 
Mobile 6), and the pings initiated from that into the direction of 
either AP or an other client are successful only in 50-60 percent, 
otherwise they timeout. The typical time is between 25-400 ms and varies 
heavily;
- the situation is the same in case of an open network and in case of 
WPA/WPA2;

All the hostapd logging facilities are on (I'm watching the syslog). 
Have been tried with compat-ath9k-20090125 and compat-ath9k-20090211, 
nothing changed. Similarly, Atheros 5416 and 9160 behaved the same.

It must be noted that with madwifi and hostapd the Samsung and iPhone 
could work perfectly, but we had to switch to ath9k.

hostapd dump contains something interesting, that may be the key to the 
problem. After the first ping to the Samsung/iPod, the status changes to 
something like this:

Before ping:
----------------------------------------------------
hostapd state dump - Wed Jun 25 13:33:05 2008
num_sta=1 num_sta_non_erp=0 num_sta_no_short_slot_time=0
num_sta_no_short_preamble=1

STA=00:21:e9:11:a3:2d
   AID=1 flags=0x23 [AUTH][ASSOC][AUTHORIZED]
   capability=0x411 listen_interval=10
   supported_rates=02 04 0b 16 0c 12 18 24 30 48 60 6c
   timeout_next=NULLFUNC POLL


ping command (ping -c 3 192.168.10.200  <-- this is the iPhone now)
----------------------------------------------------
ping -c 3 192.168.10.200
PING 192.168.10.200 (192.168.10.200): 56 data bytes

--- 192.168.10.200 ping statistics ---
3 packets transmitted, 0 packets received, 100% packet loss


After the ping (a Windows host was connected and the ping happened from 
there):
----------------------------------------------------
hostapd state dump - Wed Jun 25 13:38:00 2008
num_sta=2 num_sta_non_erp=0 num_sta_no_short_slot_time=0
num_sta_no_short_preamble=2

STA=00:80:5a:36:9d:6b
   AID=2 flags=0x23 [AUTH][ASSOC][AUTHORIZED]
   capability=0x411 listen_interval=3
   supported_rates=82 84 8b 96 0c 12 18 24 30 48 60 6c
   timeout_next=NULLFUNC POLL

STA=00:21:e9:11:a3:2d
   AID=1 flags=0x63 [AUTH][ASSOC][AUTHORIZED][PENDING_POLL
   capability=0x411 listen_interval=10
   supported_rates=02 04 0b 16 0c 12 18 24 30 48 60 6c
   timeout_next=NULLFUNC POLL


This "[PENDING_POLL" doesn't seem to be totally OK to me...


hostapd.conf:
----------------------------------------------------
interface=wlan0
driver=nl80211
ieee80211n=1
hw_mode=g
country_code=DE
max_num_sta=32
# supported_rates=10 20 55 110 60 90 120 180 240 360 480 540
# ht_capab=[HT40-][SHORT-GI-20][SHORT-GI-40]
logger_syslog=1
logger_syslog_level=0
logger_stdout=-1
logger_stdout_level=0
debug=1
ctrl_interface_group=0
macaddr_acl=0
auth_algs=1
dump_file=/tmp/hostapd.dump
ctrl_interface=/var/run/hostapd
ssid=norbolataska
wpa=3
wpa_key_mgmt=WPA-PSK
wpa_pairwise=CCMP
rsn_pairwise=CCMP
ap_max_inactivity=15
wpa_psk=af8f7d04a3331126ee9fad0cf2dbba54728389d93d83ca1549dfda2727249890
channel=13


Both hostapd-0.6.7 and 0.6.8 produce the symptoms described above.

Do you have any idea what could be wrong? Why is there problems with 
iPhone and Samsung i780? I was unable to figure out. Both phone receive 
the correct DNS, gateway and IP data. If my DNS server or DHCP server 
would be wrong then how could other devices work seamlessly?

Any idea/information is appreciated...

Thank you very much!

Best regards,

(I can send my hostapd compile-time configuration on request)
-- 
Tamas Selmeci
R&D Engineer



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