I have a Doubt regarding NAT mechanism provided by the routers/Modem. We know that private IPs assign to a device is dynamic using NAT mechanism it can differ for a device w.r.t to time means it can be changed. Lets Suppose a device having an IP address of 192.168.2.5 and that device sent an Email to a particular server (IP is 30.78.76.55 )through Internet and in NAT table router has stored this information means this combination along with external and private port, Now my question is After some days IP of that particular device got changed to 192.168.2.10 then how does router will map the response coming from that server (IP is 30.78.76.55 ) in which it was previously requested?
