Similarly, I found that OP's article provided an excellent primer on many concepts -- it certainly clarified the relationship between NAT and firewalls: that is

Similarly, I found that OP's article provided an excellent primer on many concepts -- it certainly clarified the relationship between NAT and firewalls: that is, the latter being somewhat of an unintended consequence of the former. Stumbling upon a great blog post that makes something click is always a pleasant experience.