Typically "your OS" doesn't do NAT in IPv4, unless your using a NAT router as your end user device. And surely you can do NAT with IPv6, Google for NAT66, but

Typically "your OS" doesn't do NAT in IPv4, unless your using a NAT router as your end user device. And surely you can do NAT with IPv6, Google for NAT66, but your average Linux box can do it. It's just almost never needed.