I have a question about sniffing on networks. I know that it is possible to sniff on a wired network, even without an IP address, and i know it is possible to sniff on an unencrypted or encrypted wireless network, but is it possible for someone to have cracked my WEP key, sit on my network and sniff or communicate on my network w/o an IP address? Using a wireless IDS (kismet), i can see that my access point has packets going through the air, even though my laptop is turned off. I checked in my linksys web-based management page and there are no other MAC addresses assigned. someone could be using a static IP, but can they be listening or communicating w/o an IP address?