Can't NAT-like devices be just as viable as a security device as well? Is the ISP willing to take responsiblity for security breaches on my home network because they banned my firewall? From a political/public-perception standpoint, treat those ISPs that are complaining about NAT as being soft on security and encouraging hacking. In todays paranoid political climate, there might even be some milage here. I have Charter pipeline in Madison, WI, and they've been very open about people using NAT devices to the point that they are recommended in some cases as security devices as well as being sold by Charter's professional-services group as inexpensive firewalls. About six months ago I got a 1-page flier from Charter offering a 4-port Linksys and an on-site installation. Since a "NAT device" could include virtually any operating system and any PC with two or more ethernet ports, it might be better to push the "firewall" aspects of them rather than try to defend or justify the MANY-to-1 routing aspects of NAT.