If I call you, Mr. Software Vendor, and explain a problem I'm having, then you ask me what my IP address is, THEN I say "192.168.x.x" for Mr. Software Vendor's server, AND THEN you try to connect to my machine over the internet to my private IP address space, you deserve a beat down for stupidity. Same thing for the 10.x.x.x network. And 172.16.x.x. I think paper cuts with a printout of RFC1918 would be a good start...