I have a much easier time understanding PAT than NAT addressing. My question is on how NAT identifies an incoming packet target adress on the internal network.
PAT uses ports as identifiers, but what about NAT?
With NAT there are 3 possibilities:
1.) multiple private addresses in local network (inside local) get mapped to single public IP (inside global) --> This is PAT or overloaded NAT
private IPs are distinguished by port from outside
2.) single private to single public -> Basic NAT, it has a table of translations, this is called Static NAT
3.) multiple private to pool of public IPs -> this is called Dynamic NAT
, it will choose some public IP from pool for every host
If you want to do true address-only NAT without getting port translation involved, you must have the same number of addresses on one side as the other. So the first public address matches to the first private address, the second to the second, the third to the third, and so on, to the end of the address pool.