Wireless Router w/ethernet cable

Problem involving a Linksys wireless-G router.

All the computers in our house connect wirelessly.  However, a friend of mine brought over his laptop and is connecting to the router with an ethernet cable.  He's not getting a connection at all.  The router does have a password on it for wireless connections.

What are we missing to make this work?

Do you have DHCP or MAC filtering enabled? Those could interfere. Besides that, some routers close down wlan <=> lan connections for security reasons.

If you do have dhcp enabled, check his IP settings and make sure he's not static. But if he is, change his to your networks scheme.