Maximum PC

Is there a way to have a router keep a list of computers (names, and MAC addresses) of devices/computers that connect to it, even if they just connect for a second, and then disconnect)?

I want to keep track of usage for my router, and to make sure that nobody outside can get in (or has gotten in) but I don't care to keep checking on a daily, semi-daily basis. I have a DLink DIR-655 Wireless N gigabit router. I know that it keeps track for a while, but then flushes the list after a day or two, or whenever the router is power-cycled. Is there a more permanant way to find this information out?

Yes, I have security enabled (WPA/WPA2), but just want to be sure anyway. I'm mainly worried about wireless connection more than wired connections, but ifi I could find a way to track both, that's be great too.

Does your DHCP service have any logging functions?

It may... I have to check. If so, this would do what I'm looking for?