Long delays for a DCHP ACK message being sent after connecting to the Access Point

john dowd jdowdster at gmail.com
Fri Jan 23 09:02:38 EST 2009


I have a capture below and although it's not clear to me (and I've
checked the dhcpd.conf file) I would think that the offer is done as a
unicast.

wpa_group_rekey = 600

I did not change it from the original file.

I have here a capture of a successful negotiation...

Capturing on wlan0
  0.000000 AcctonTe_8f:06:6b -> Broadcast    XID Basic Format; Type 1
LLC (Class I LLC); Window Size 0
  3.083495 AcctonTe_8f:06:6b -> Broadcast    XID Basic Format; Type 1
LLC (Class I LLC); Window Size 0
 26.331969 AcctonTe_8f:06:6b -> Broadcast    XID Basic Format; Type 1
LLC (Class I LLC); Window Size 0
 26.501794 AcctonTe_8f:06:6b -> 00:22:b0:5e:50:ff EAPOL Key
 26.538003 AcctonTe_8f:06:6b -> 00:22:b0:5e:50:ff EAPOL Key
 35.664550      0.0.0.0 -> 255.255.255.255 DHCP DHCP Discover -
Transaction ID 0x8cd526d
 35.664545      0.0.0.0 -> 255.255.255.255 DHCP DHCP Discover -
Transaction ID 0x8cd526d
 35.666634 00:22:b0:5e:50:ff -> Broadcast    ARP Who has 192.168.1.20?
 Tell 192.168.1.1
 35.854743  192.168.1.1 -> 192.168.1.20 DHCP DHCP Offer    -
Transaction ID 0x8cd526d
 35.927674      0.0.0.0 -> 255.255.255.255 DHCP DHCP Request  -
Transaction ID 0x8cd526d
 35.927670      0.0.0.0 -> 255.255.255.255 DHCP DHCP Request  -
Transaction ID 0x8cd526d
 35.950226  192.168.1.1 -> 192.168.1.20 DHCP DHCP ACK      -
Transaction ID 0x8cd526d
 35.951691  192.168.1.1 -> 192.168.1.20 DHCP DHCP ACK      -
Transaction ID 0x8cd526d

What I find interesting is that the line containing EAPOL Key seems to
always occur just before a successful negotiation. If these lines
don't happen then the negotiation never completes.

I've also in my posesion a mobile phone that is wifi enabled that can
not see the hostapd Access Point. It can see all the others around my
office area but it just can't see mine. All of the other devices can
see mine as well. I ask it to do a scan and it will never list the
hostapd Access Point. I can see that hostapd sees the scan and
replies. Unfortunately the other phone is a consumer product and
closed to me and I can't get into it and check error logs or look for
fault codes of any kind whereas the Openmoko phone is a Linux based
device and fully open.



On Fri, Jan 23, 2009 at 6:23 AM, Jouni Malinen <j at w1.fi> wrote:
> On Thu, Jan 22, 2009 at 10:30:05AM -0500, john dowd wrote:
>
>> Occasionally, I get the scenario that the system is performing as per
>> described above up until the remote device is sending the DHCP
>> Discover packets. The Access Point side is sending the DHCPD Offer
>> packets but they just don't seem to be seen by the remote device. This
>> can go on for hours and then, the remote device will send an ACK and
>> we have a connection. I see no errors while this is going on. I do see
>> some activity from hostapd that I would expect since I would gather
>> that the wireless connection needs some maintenance but no errors are
>> obvious.
>
> Does your DHCP server send the DHCP Offer as a unicast or broadcast
> packet? How have you configured group rekeying (wpa_group_rekey in
> hostapd.conf)?
>
> --
> Jouni Malinen                                            PGP id EFC895FA
> _______________________________________________
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> HostAP at lists.shmoo.com
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>



-- 
    John Dowd

    133 Waverley St.
    Ottawa Ont. K2P 0V3
    Home: (613)234-7884
    Cell: (613)316-7884
    email: jdowdster at gmail dot com


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