Hello, I am new to the Airport Extreme routers. My old router (D-Link DIR-655) was giving me CONSTANT DNS issues. This is apparently very common with that DLink Router. Anyway, once I got my Airport Extreme set up, I ran GRC Shields Up! It listed most of my ports as closed instead of Stealth. Do I need to worry? Did I miss a setting when I was configuring it? Does it have a firewall? Thanks.