&gt; Just go back to the early 00s or mid-90s to see the ramifications that exposing ports from Windows machines to the Internet had, then tell me NAT hasn&#x27;t had a positive security impact.<p>NAT has had the same _security_ impact that a default REJECT ingress firewall policy would have. (Coincidentally, this is the default firewall policy for non-Enterprise Windows Firewall configurations.)<p>If you combine default REJECT with a port opening protocol like uPnP, you have a really nice, reasonably secure, self-maintaining border firewall. (Hyperventilation about security issues with particular implementations of uPnP notwithstanding.)