How can you make many computers have the same IP address?

Answer 1

Use a router.

Connect your cable or DSL modem to router, router to hub. Some cable and DSL modems have built-in capabilities to act as a router and perform Network Address Translation (NAT). The router can assign separate IPs for each computer, but all will access the internet through the 1 IP address assigned to the port of the router/modem connected to the Internet service provider's network.

If you are using a slower dial-up modem, the computer connected to the Internet using the modem can have 'Internet Connection Sharing' turned on. This computer will connect to other computers in your home using a hub/switch. The other computers will use the modem connected computer as their Default Gateway.

Alternatively... We can have same ip address on two or more computers in the SAME network. They should be in same collission domain. Let their MAC address be same first & then assign them same ip address. You can do it by installing a cheap network hub. Watch my associated video on www.metacafe.com/channels/austinium2002/

Answer 2

You use a proxy, an intermediate server that forwards the requests on behalf of the other computers. The server that sends the response will see only the IP of the proxy, so from the perspective of the public server there is only one computer and one IP.

If you have a home broadband connection and a router, that's what you already have. You can connect several computers to the router, and they will have different IP addresses on your local network, but they share a single public IP.
For standard home broadband, the public IP is assigned by the ISP and cannot be changed by the subscriber. The public IP is independent of the IPs used on the local network.

See related link for whatismyip.com, one of several sites that can show you your public IP.

Answer 3

On the same subnet, no - that would cause problems. On different subnets, yes - if there is some address translation in place. For example, many companies use private addresses starting with 10.0.0...., so there are probably thousands of computers worldwide that have the address 10.0.0.2, 10.0.0.3, etc. - but those addresses are not visible to the outside word, because of the address translation (NAT).

On the same subnet, no - that would cause problems. On different subnets, yes - if there is some address translation in place. For example, many companies use private addresses starting with 10.0.0...., so there are probably thousands of computers worldwide that have the address 10.0.0.2, 10.0.0.3, etc. - but those addresses are not visible to the outside word, because of the address translation (NAT).

On the same subnet, no - that would cause problems. On different subnets, yes - if there is some address translation in place. For example, many companies use private addresses starting with 10.0.0...., so there are probably thousands of computers worldwide that have the address 10.0.0.2, 10.0.0.3, etc. - but those addresses are not visible to the outside word, because of the address translation (NAT).

On the same subnet, no - that would cause problems. On different subnets, yes - if there is some address translation in place. For example, many companies use private addresses starting with 10.0.0...., so there are probably thousands of computers worldwide that have the address 10.0.0.2, 10.0.0.3, etc. - but those addresses are not visible to the outside word, because of the address translation (NAT).

Answer 4

On the same subnet, no - that would cause problems. On different subnets, yes - if there is some address translation in place. For example, many companies use private addresses starting with 10.0.0...., so there are probably thousands of computers worldwide that have the address 10.0.0.2, 10.0.0.3, etc. - but those addresses are not visible to the outside word, because of the address translation (NAT).

Answer 5

You can't. Not even with an IP spoof attack.