I tried Free Ping Tool, the latest version, in my company LAN. It works well with www.google.com and any server LAN IP addresses but doesn't work with firewall LAN IP adresses. Indeed, the status is RED and I have no reply (RTT = 0, Success = 0, Failed = 0) whereas when you ping these firewall in a MSDOS windows, it works.

Any idea about the cause of this issue?