Re: DHCP over bridge between WiFi and wired

[Barak Pearlmutter <barak@cs.may.ie>]

Running iptraf on the bridging laptop while the bridge was up, I saw
the DHCP packets flow from the phone across the bridge and out the
wireless side:

  UDP (332 bytes) from 0.0.0.0:bootpc to 255.255.255.255:bootps (src HWaddr 000b82002fce) on eth1 (WIRED interface)
  UDP (332 bytes) from 0.0.0.0:bootpc to 255.255.255.255:bootps (src HWaddr 000b82002fce) on eth0 (WiFi interface)

But no response.  Then I unplugged the laptop from the hub the phone
was on, and instead plugged the hub into another hub which I'd
inserted between the WAP and its uplink.  Then iptraf saw the phone
DHCP again ... and saw the WAP respond.

  UDP (332 bytes) from 0.0.0.0:bootpc to 255.255.255.255:bootps (src HWaddr 000b82002fce) on eth0 (WiFi interface)
  UDP (332 bytes) from 10.11.13.38:bootps to 255.255.255.255:bootpc (src HWaddr 00032f0cc888) on eth0

What's up with *that*?

Can WAPs filtering out packets that come via a particular wireless
client but don't match its MAC address - ie do they have enough
"extra" info (as part of the extra stuff in the 802.11b protocol to
even make that determination?  It's my own WAP, and I certainly didn't
turn on any MAC filtering or anything like that.
--
Barak A. Pearlmutter <barak@cs.may.ie>, http://www-bcl.cs.may.ie/~barak/
 Hamilton Institute, NUI Maynooth, Co. Kildare, Ireland