from communicating with its owner. A PS3 is far different than your average computer so don't worry about putting that on a DMZ). A firewall is a relatively simple tool that isnt capable of ensuring the best online security possible. But IPv4 - which supports only about.2 billion addresses - has run out of addresses. Secondly, it requires every incoming packet of information to have been asked for by a device. If your OS offers its own built-in firewall, we recommend switching. If you want to ensure the best online security possible, you should add NordVPN to the mix. However, a NAT firewall is not enough. Nucleic Acid Amplification Testing, medical, nAT.