[ath9k-devel] DHCP Fails to Pass Through AP

[Pat Erley <pat-lkml@erley.org>]

Jason Daly wrote:
> Hello,
> 
> When connecting Windows (XP/Vista) wireless clients to a hostapd AP, 
> DHCP offers do not succeed.  When setting the network interface settings 
> on the client to use a static configuration connectivity succeeds and 
> client networking through the AP functions well.
> 
> A high-level layout of my network is as follows:
> 
> - Linux router running hostapd: 192.168.8.1
> - Windows Server 2003 DC running DHCP: 192.168.8.20
> - Windows XP/Vista clients
> 
> Following are details of the router running hostapd:
> 
> - Bridge interface: br0
> - Interfaces attached to the bridge: wlan0, eth1
> - Bridge IP: 192.168.8.1
> 
> DHCP is working and the bridge functions: I have confirmed this by
> successfully
> obtaining a DHCP lease via the notebook's LAN port.
> 
> I am using the following software versions:
> 
> - hostapd 0.6.9
> - FC10(2.6.29.1-15.fc10.i686)
> - ath9k
> 
> Following are the contents of my hostapd.conf file:
> 
> bridge=br0
> interface=wlan0
> driver=nl80211
> ssid=myessid
> hw_mode=g
> channel=6
> eapol_version=1
> logger_syslog=-1
> logger_syslog_level=2
> logger_stdout=-1
> logger_stdout_level=2
> ctrl_interface=/var/run/hostapd
> ctrl_interface_group=0
> macaddr_acl=0
> deny_mac_file=/etc/hostapd.deny
> auth_algs=3
> eapol_key_index_workaround=0
> eap_server=0
> dump_file=/tmp/hostapd.dump
> wpa=3
> wpa_key_mgmt=WPA-PSK
> wpa_pairwise=TKIP CCMP
> wpa_psk=*********
> ieee8021x=0
> 
> 
> Is there a setting in hostapd that must be added to allow DHCP to pass
> through
> the bridge.  UDP works fine through the bridge, as the client can see the
> Windows domain and can broadcast for clients on the domain (when connected
> via
> a static IP or via a physical LAN cable).
> 

I'm using ath9k w/2.6.29.1+Compat-Wireless for an access point and have no
such problems.  Not that it should affect your setup, but auth_algs could be
set to 1 instead of 3, as you don't define any WEP keys anyways, so there's 
not shared auth available.  I have had problems with having CCMP set and some
windows clients with my AP, so I have : 

wpa=3
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
rsn_pairwise=CCMP

So that wpa only uses TKIP, and wpa2 only uses CCMP, but again, that shouldn't
affect dhcp.  Tried restarting dhcpd after hostapd?  Maybe hostapd startup is
causing dhcpd to get wonky.  Aside from that, I'd suspect something in your
firewall rules and/or something in your dhcpd.conf.

Pat Erley