hostap AP connected but cannot ping

Wed Jun 15 22:56:04 EDT 2011

Hi David,

The problem is not seen now.  The issue was with the ath9k driver. I have
compiled and installed the latest version of ath9k and it works fine.
Thanks for your time.

Thanks,
Uday.

On Mon, Jun 13, 2011 at 3:38 PM, Uday Yeddula <uday.yeddula at gmail.com>wrote:

> Hi David,
>
> I do not have iptables filtering in both AP and laptop.
>
> Some more information:
> The ping from laptop to AP does not always fail. Some times its successful
> and some times it fails. Its not consistent.
> I have encountered scenarios where in a single run of ping command, the
> ping succeeds for initially and then fails after some time as below:
>
> uday at uday:~$ ping 172.16.1.1
> PING 172.16.1.1 (172.16.1.1) 56(84) bytes of data.
> 64 bytes from 172.16.1.1: icmp_req=1 ttl=64 time=14.8 ms
> 64 bytes from 172.16.1.1: icmp_req=2 ttl=64 time=1.01 ms
> 64 bytes from 172.16.1.1: icmp_req=3 ttl=64 time=1.00 ms
> 64 bytes from 172.16.1.1: icmp_req=4 ttl=64 time=1.39 ms
> 64 bytes from 172.16.1.1: icmp_req=5 ttl=64 time=1.05 ms
> 64 bytes from 172.16.1.1: icmp_req=6 ttl=64 time=6.68 ms
> 64 bytes from 172.16.1.1: icmp_req=7 ttl=64 time=1.79 ms
> 64 bytes from 172.16.1.1: icmp_req=8 ttl=64 time=0.980 ms
> From 172.16.1.11 icmp_seq=37 Destination Host Unreachable   <<<< Fails from
> here
> From 172.16.1.11 icmp_seq=38 Destination Host Unreachable
> From 172.16.1.11 icmp_seq=39 Destination Host Unreachable
> From 172.16.1.11 icmp_seq=40 Destination Host Unreachable
>
> I have to restart the hostapd deamon after this for the ping to work
> normally.
>
> Thanks,
> Uday.
>
>
>
> On Mon, Jun 13, 2011 at 3:29 PM, Davide <louigi600 at yahoo.it> wrote:
>
>> Do you have iptables filtering in either laptop or AP ?
>>
>> --- *Lun 13/6/11, Uday Yeddula <uday.yeddula at gmail.com>* ha scritto:
>>
>>
>> Da: Uday Yeddula <uday.yeddula at gmail.com>
>> Oggetto: Re: hostap AP connected but cannot ping
>> A: "Davide" <louigi600 at yahoo.it>
>> Cc: hostap at lists.shmoo.com
>> Data: Lunedì 13 giugno 2011, 05:46
>>
>>
>> Hi David,
>>
>> Thank you for replying.
>>
>> Yes, I have assigned ip-address to the wireless interface in AP mode.
>> As I wrote in my previous e-mail, when I ping from my laptop to the device
>> in AP mode, the device responds to the ARP requests and the ICMP echo
>> requests with ARP replies and ICMP echo replies. But, the replies are not
>> received by my laptop.
>> The "tcpdump" captures on the wireless interface in AP mode, when an ICMP
>> request is sent from my laptop are as below:
>>
>> ====> when ARP entry for the wireless interface in AP mode is not present
>> in my laptop,
>> *user at user:~$ sudo tcpdump -i wlan2
>> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
>> listening on wlan2, link-type EN10MB (Ethernet), capture size 96 bytes
>> 11:17:58.729002 ARP, Request who-has 172.16.1.1 tell 172.16.1.11, length
>> 28
>> 11:17:58.729024 ARP, Request who-has 172.16.1.1 tell 172.16.1.11, length
>> 28
>> 11:17:58.729033 ARP, Reply 172.16.1.1 is-at 00:26:b6:de:f3:9b (oui
>> Unknown), length 28
>>
>> =====> when ARP entry is present on my laptop
>> user at user:~$ sudo tcpdump -i wlan2
>> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
>> listening on wlan2, link-type EN10MB (Ethernet), capture size 96 bytes
>> 11:23:53.568172 IP 172.16.1.11 > 172.16.1.1: ICMP echo request, id 11220,
>> seq 15, length 64
>> 11:23:53.568222 IP 172.16.1.1 > 172.16.1.11: ICMP echo reply, id 11220,
>> seq 15, length 64
>> *
>> So, suspecting either the packets are lost in air or mishandled by the
>> wireless driver (ath9k + hostapd).
>> Any thoughts on this?
>>
>> Thanks,
>> Uday.
>>
>> On Sat, Jun 11, 2011 at 9:39 AM, Davide <louigi600 at yahoo.it<http://mc/compose?to=louigi600@yahoo.it>
>> > wrote:
>>
>> Have you given your wireless interface in AP mode an ip address ?
>> If you don't do that you will not be able to ping it.
>> You could also try bridging lan and wlan in one virtual interface allowing
>> bothe to be seen with the same address.
>>
>> Regards
>> David
>>
>> --- *Ven 10/6/11, Uday Yeddula <uday.yeddula at gmail.com<http://mc/compose?to=uday.yeddula@gmail.com>
>> >* ha scritto:
>>
>>
>> Da: Uday Yeddula <uday.yeddula at gmail.com<http://mc/compose?to=uday.yeddula@gmail.com>
>> >
>> Oggetto: hostap AP connected but cannot ping
>> A: hostap at lists.shmoo.com <http://mc/compose?to=hostap@lists.shmoo.com>
>> Data: Venerdì 10 giugno 2011, 12:50
>>
>>
>> Hi,
>>
>> I am trying to configure an embedded device as an Access Point. It has
>> Atheros Communications Inc. AR928X Wireless Network Adapter (PCI-Express). I
>> have Ubuntu 9.10 Server version installed in the box. ("2.6.31-14-generic
>> #48-Ubuntu SMP"). Using hostapd deamon with ath9k driver for the same.
>>
>> I have built hostapd using libnl-dev and libssl-dev packages.
>> After starting the hostapd with the hostapd.conf (sudo ./hostapd
>> hostapd.conf), tried connecting my laptop to this AP.
>> The connection was successful but cannot ping from my laptop to the AP.*
>>
>> user at user:~$ sudo hostapd /etc/hostapd/hostapd.conf
>> Configuration file: /etc/hostapd/hostapd.conf
>> Using interface wlan2 with hwaddr 00:26:b6:de:f3:9b and ssid 'test'
>> wlan2: STA 00:26:82:c9:d3:30 IEEE 802.11: authenticated
>> wlan2: STA 00:26:82:c9:d3:30 IEEE 802.11: associated (aid 1)
>> wlan2: STA 00:26:82:c9:d3:30 RADIUS: starting accounting session
>> 4DF1F33A-00000000
>> *
>> On further analysis found that, my laptop sends the ARP request to the AP
>> box. The AP box sends the ARP reply (observed using tcpdump on the AP box)
>> but my laptop cannot see the ARP reply.
>> If I restart hostapd deamon at this point, it works fine. (My laptop can
>> ping the AP).
>> The AP is not stable. my laptop can always connect to it. But some times
>> the ping to the AP fails.
>>
>> Has any one seen similar issue? Can you help me with the fix for this
>> problem?
>> I have tried both hostapd-0.6.9 and hostapd-0.7.3 versions and found same
>> problem on both versions.
>>
>> The hostapd.conf used is as follows:
>>
>> hostapd.conf:
>>
>> interface=wlan0
>> driver=nl80211
>> ssid=test
>> channel=11
>> hw_mode=g
>> macaddr_acl=0
>> auth_algs=0
>> ignore_broadcast_ssid=0
>>
>> Thanks,
>> Uday.
>>
>> -----Segue allegato-----
>>
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>>
>>
>
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