It really depends if the public IP that is provided via your gateway (cable, DSL, etc.) response to ICMP. As others mentioned there is a big possibility that the gateway does not respond to ICMP requests. if you have the option to change it on the gateway, then the should work. Otherwise, I don’t think you’d be able to successfully ping the gateway’s public IP address directly. One way to get around this would be to set up port forwarding on your router to a system on the network that is powered and responds to ICMP requests successfully. I can’t think of what the port for ICMP off the top of my head (I think it’s 7). As the last resort, you can enable DMZ on the router if you’re having issues setting up the port Ford. I would suggest that you remove the DMZ rule as fast as possible, as that would expose a local area network client to the internet directly.