Alot of home router have the option to block ICMP traffic from the WAN. I can't seem to find this with the Airport Extreme Base Station. Using Gibson Research Corporation's Shields Up! I get the following messages: Solicited TCP Packets: RECEIVED (FAILED) As detailed in the port report below, one or more of your system's ports actively responded to our deliberate attempts to establish a connection. Ping Reply: RECEIVED (FAILED) Your system REPLIED to our Ping (ICMP Echo) requests, making it visible on the Internet. All other ports scanned came back with: Closed - Your computer has responded that this port exists but is currently closed to connections. or Stealth - There is NO EVIDENCE WHATSOEVER that a port (or even any computer) exists at this IP address! I'm no network guru, but shouldn't all port scan attempts come back as stealth? Shouldn't the router not respond to Pings on the WAN side?