Well /ping google.com
Result: N/A
.... SO then i found the problem... You can set in some firewalls (in this case in my router) to block ping requests.
So it seems you check quality with ICMP Ping.
Just a toguht: maybe you should use an IRC related pinging ("Ping? Pong!"), which can resolve this problem, and maybe not a big deal to accomplish.
Well, ok, thanks for the help anyways.