302 | | |
303 | | |
| 302 | === 10/05/2010 === |
| 303 | |
| 304 | After some experiments we discovered that the arp replies never get transmitted by the clients them selves. This is apparently a design feature intended to prevent arp table poisoning, and merging of the wireless and wired Ethernet broadcast domains. It's then the job of the access point, (the bridge in specific) to answer arps on behalf of the hosts on opposite sides of the bridge. This was confirmed by running a capture in the air and on the wire simultaneously, then originating a ping from the wired side in the winlab network with CISCO ap. On the originating client I can see an arp request go out and an arp reply come back, but in the air an independent listener sees the arp request but not the reply. |
| 305 | |
| 306 | The next step was to check if the Linux bridge tools did this as well. I installed a baseline system and then installed hostapd and bridge-utils. |
| 307 | |
| 308 | I modified hostapd in a similar fashsion, and used brctl to create a br0 and added the interfaces to it. Initally this did not work but looking at the [http://en.gentoo-wiki.com/wiki/Atheros_Ath5k_Wireless_Access_Point refrence] , it was pointed out that I needed assign an ip to the bridge interface as well. I guess the bridge interface needs an IP to craft packets IP packet responses, even tho this ip had nothing to do with the subnet I was passing traffic for, |