NAT (Network Address Translation) is what allows all your devices share one public IP address. Inside your home network, everything uses private addresses like 192.168.0.x. When devices talk to each other locally, like copying files or printing, those private addresses are all that’s needed.
But when you go out to the internet, your traffic goes through your router (often at 192.168.0.1). The router keeps a small table that tracks which device made which request. It then sends the request to the internet using your single public IP address, not your internal one.
When the response comes back, the router checks its table, sees which internal device asked for it, and forwards the data back to the correct private IP.
A simple way to picture it: Your IP address is like a street address, and the port number is like the apartment number.
So inside your network, devices use private IPs like 192.168.0.x. Outside your network, everything appears to come from your one public IP, thanks to NAT.
No such thing, we need basics at times so we all learn and understand also being able to communicate clearly an important part of your own understanding.
Okay, understand. Internal IP address and a public IP address for outside the home.
A little deeper. Let say my public IP address is 96.255.240.103 and I try to link to a web page across country or overseas. My request will go thru unknown number of servers and the site will send me back a response. So is my IP address just like a mailing address that will ID the country, state, city, street, and home? But in the case of the public IP address, it may ID the ISP provider who in turns knows who I am.
Yes. If IP v6 is supported on your home Network (and this is becoming more common), your computer has two IP addresses, one for the IP v4 standard, and a much longer one for the IP v6 protocol. The IP v6 protocol provides the capacity for several orders of magnitude more IP addresses, so the Internet won’t run out of available addresses any time soon, if ever. Although, as long as your computers and modem/router retain support for IP v4, your home Network will still be able to use that protocol if you want it to. In that case, your modem/router will have an IP v6 WAN address, and the NAT protocol will still be able to handle the address translation for your computer’s IP v4 address to the modem/router’s IP v6 address for transmission over the Internet.
I’m not nearly as well versed on IP v6 as I am with IP v4, so I’ll leave it to others who fully understand what it contains, and how it works to fill in those gaps, at least until I learn more.
AFAIK, eventually it will have to, and IP v4 will become deprecated at some point, simply because there are no longer any IP v4 websites remaining on the Internet, and by then, all ISPs will have added support for IP v6 too. But that time may not come in my lifetime because so many websites retain their current IP v4 address, and won’t change until it becomes a requirement, or needed to remain in business.
Your computer’s address (192.168.x.x) is known only to your modem/router, because when it forwards any communication from your computer to a website on the Internet your modem/router’s Internet facing (WAN) IP address is used. As I understand it, each connection between any computer on your home Network, and any website on the Internet includes a unique identifier that both your modem/router and the website being communicated with use to keep track of that communication. In the case of your modem/router, that identifier is used to associate that connection with your computer, and for the website, it associates the data packets coming and going with your connection/session.
