How computers in a LAN can share one IP address?

Answer 1

Every entity on a network needs a unique address, but there are ways to 'fake out' the Internet.

Most routers do this by using NAT (Network Address Translation).

What NAT does is allow the router to talk to the Internet with one IP address (like 192.23.145.22) and talk to its own computers using internally generated addresses that the Internet doesn't see. Only the router and the computers attached to the router see these addresses. The router uses addresses like 192.27.0.0, 192.27.0.1, 192.27.0.2, and so on - this allows each attached computer to have a unique IP address when it talks to the router.

The router then performs the NAT processing necessary to correctly map traffic on the internal addresses to the real Internet address.

As far at the Internet is concerned, it is talking to a single IP address.

As far as each computer is concerned, it has its own unique IP address.

The router does all the work.

I hope this was helpful!

Answer 2

Two computers cannot have the same IP Address but with a router, the router can act as a Gateway where the Gateway is connected to your one IP Address and then the Gateway assigns IP Addresses to all computers connected to the router. I have a wireless router that does this for my home network which only has one IP connection to the outside world but has three computers connected to the router and they all get to the outside world!

Answer 3

When using a NAT gateway, the number is limited only by the number of private IP addresses. Well into the millions.

We have over10,000 users routing through a single NAT gateway. Needless to say it's pretty heavy duty but it works quite nicely.

Answer 4

NAT - network address translation. When PC 1 requests a web page, it passes through a server that assigns all the IP addresses to machines on its network. It attaches information on the packet that tells it which PC asked for what. When the information comes back, it looks at that stamp to determine which PC to route the information to. This happens many times on the internet, from home network -> ISP -> internet -> other network and back.