I have a linksys wireless router with dd-wrt firmware installed. The router is also my gateway. I have a few computers behind the router. Now, when I connect via wireless I use
iwlist wlan0 scan

and I find my essid with a certain mac address for the linksys router. I connect easily with

iwconfig wlan0 essid xxxx
iwconfig wlan0 ap xx:xx:xx:xx:xx:06
iwconfig wlan0 key xxxxx
dhclient

However, when I check my arp cache I notice xx:xx:xx:xx:xx:04 as the mac address of my router. Why is the mac address last digit different?

From man iwconfig :So I guess it's not possible as the MAC of your AP is xx:xx:xx:xx:xx:04

So it just associates with your AP from the ESSID and key.

Interesting gonna test that out tonige by just inputing the essid and the key

I tested it out. I did

iwconfig ath0 essid xxx
iwconfig ath0 key xxx
dhclient ath0

and it worked!!. Then I ran

iwconfig ath0

and the Access Point read xx:xx:xx:xx:xx:06

So I ran

arp -a

and still the gateway(router and wireless ap) said xx:xx:xx:xx:xx:04

Why is that?

I've seen before on some modems where the mac address are listed and it usually lists two, each 2 integers apart like in this case. Which is which tho? I guess maybe, the gateway side would be xx:xx:xx:xx:xx:04 because it comes out on arp and the access point would be xx:xx:xx:xx:xx:06 because it's accessed from the inside, or maybe the wireless ap in the router has a separate nic just for wireless and a different mac (2 digits less) for ethernet.