What type of protocol is used to present a public ip address to computers outside the lanto handle requests to use the internet from computers inside the lan?

Answer 1

It's called NAT and it stands for Network Address Translation.

IP addresses are mapped from inside to outside addresses, transparent to end users. There are three different types of NAT (Static, Dynamic, and Overloading). The most common is NAT overload or sometimes called Port Address Translation (PAT).

It maps an inside private address like 192.168.1.2 to a public address on your home router like 208.67.220.221. The problem is that you only have one public address on your home router, so we use TCP or UDP ports to identify different inside address. For example your web browser connects to a web server using a source port of 50,000. The router makes a table and swaps out the original source address and port (192.168.1.2:50000) to an outside public address and port number (208.67.220.221:50000). When the web server responds back, it sends it to the outside address and port number of 208.67.220.221:50000. The router has a table and knows which inside computer to send this to.

The main reason we use this protocol is because we are running out of IPv4 addresses pretty fast. If we had to use a public address for every computer in the world we would have ran out of addresses a long time ago. Another reason is because private addresses are not routable on the internet like 192.168.0.1.

Answer 2

You are thinking of Network Address Translation or NAT, but it is not a protocol, rather a process that a router will use to share one address amongst many, or translate one address into another.

Answer 3

The protocol is TCP. However, the networking tecnology used is port NAT (Network Address Translation), configured on a Router and/or Firewall.

Answer 4

NAT. Network Address Resolution.

Answer 5

NAT