On Dec 10, 2014, at 7:39 PM, Doug Royer <douglasroyer@xxxxxxxxx> wrote: > What about legacy software that decides what port it is going to use? > Well their packets go to the wrong hardware? Seems a BIG security hold to me. This is equivalent to the current practice of giving a home gateway an IP address with all 64k ports. These ports are _already_ shared by devices behind the NAT. The difference with port sharing is just that you start out with fewer than 64k ports. Legacy software of the type you describe already doesn't work with a NAT.