LINUX Firewall - Ethernet bridging

our bridge is set for all nics to be bridged to no ip and so you give ifconfig a setting of promisc up which as described by the ifconfig man page means "All packets on the network will be received by the interface."

bridge name     bridge id               STP enabled     interfaces
br0             8000.001346e6250b       no                    ath1
                                                                                  eth2
                                                                                  tap0
As you can see below, ath1, eth2, and tap0 all don't have an IP because they are all in the bridge. br0, the bridge, takes all traffic that comes from the interfaces: ath1, eth2, and tap0 and "bridges" the networks in this way as if they were all on one network card, the configuration of br0 represents this "one network card". Our bridge was constructed using the howto from the OpenVPN site with a small modification that allows three interfaces on the bridge: http://openvpn.net/bridge.html

We are trying to understand why the Wireless nodes receive IPs just fine, but the Backup server noted below in the ifconfig output receives a DHCP IP address just fine and is still not able to ping anything local or remote?

Linux Server (Firewall):
ath1      Link encap:Ethernet  HWaddr 00:14:6C:89:44:87
          inet6 addr: fe80::214:6cff:fe89:4487/64 Scope:Link
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:16496 errors:0 dropped:0 overruns:0 frame:0
          TX packets:20112 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:1904165 (1.8 Mb)  TX bytes:15290428 ( 14.5 Mb)

br0       Link encap:Ethernet  HWaddr 00:13:46:E6:25:0B
          inet addr: 192.169.0.1  Bcast: 192.169.0.255  Mask: 255.255.255.0
          inet6 addr: fe80::213:46ff:fee6:250b/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:14442 errors:0 dropped:0 overruns:0 frame:0
          TX packets:15492 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:1618977 (1.5 Mb)  TX bytes:7141959 (6.8 Mb)

eth2      Link encap:Ethernet  HWaddr 00:13:46:E6:25:0B
          inet6 addr: fe80::213:46ff:fee6:250b/64 Scope:Link
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:122429276 errors:0 dropped:0 overruns:0 frame:0
          TX packets:270420109 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:887642421 (846.5 Mb)  TX bytes:2930004281 (2794.2 Mb)
          Interrupt:225 Base address:0xdc00

eth3      Link encap:Ethernet  HWaddr 00:16:EC:69:3C:B5
          inet addr: Internet.IP.12.2  Bcast: Internet.IP.12.255  Mask:255.255.255.0
          inet6 addr: fe80::216:ecff:fe69:3cb5/64 Scope:Link
          UP BROADCAST NOTRAILERS RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:8140802 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2323611 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:3906504983 ( 3725.5 Mb)  TX bytes:551977672 (526.4 Mb)
          Interrupt:209 Base address:0xd800

lo        Link encap:Local Loopback
          inet addr: 127.0.0.1   Mask: 255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:23808860 errors:0 dropped:0 overruns:0 frame:0
          TX packets:23808860 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:2245957434 (2141.9 Mb)  TX bytes:2245957434 (2141.9 Mb)

tap0      Link encap:Ethernet  HWaddr CE:3C:1D:1E:3B:41
          inet6 addr: fe80::cc3c:1dff:fe1e:3b41/64 Scope:Link
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:704 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100
          RX bytes:0 (0.0 b)  TX bytes:180832 ( 176.5 Kb)

wifi0     Link encap:UNSPEC  HWaddr 00-14-6C-89-44-87-00-00-00-00-00-00-00-00-00-00
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:16605879 errors:0 dropped:0 overruns:0 frame:1080636
          TX packets:11432729 errors:65368 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:199
          RX bytes:2162385966 ( 2062.2 Mb)  TX bytes:748681877 (713.9 Mb)
          Interrupt:209 Memory:cf080000-cf090000

Backup Server:

eth0      Link encap:Ethernet  HWaddr 00:10:5A:01:96:0D
          inet addr: 192.169.0.3  Bcast: 192.169.0.255  Mask:255.255.255.0
          inet6 addr: fe80::210:5aff:fe01:960d/64 Scope:Link
          UP BROADCAST NOTRAILERS RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1558 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1304 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:198584 (193.9 Kb)  TX bytes:125200 ( 122.2 Kb)
          Interrupt:9 Base address:0xdf00

lo         Link encap:Local Loopback
          inet addr: 127.0.0.1  Mask: 255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:94 errors:0 dropped:0 overruns:0 frame:0
          TX packets:94 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:6804 (6.6 Kb)  TX bytes:6804 (6.6 Kb)