Hi every one,

Is it possible to connect 2 computers having the same IP address, gateway, etc to the internet using an office network at the same time?

The network has a central IP address and each computer is assigned a specific (internal) IP address.

How can it it be done and what are the implications?

Thanks in advance for you help.

Hi waki

I'm not sure if you meant for the computers to have the same internal IP address or if you just needed for them to have the same external IP address. If on the internal network you have the same IP address, then an error will usually occur, something like this IP address is already in use on the network. I've seen where users have been kicked off because the 2nd computer "turns on" and I've seen where it simply doesn't let the 2nd computer join. I'm not sure on the specifics that causes that to happen

If you need the same IP address externally, doesn't sound like a problm if there is an internal address. The router should interface everything correctly (assign the computers their internal IP and maintain one external IP that the world sees).

What normally happens when you wish to connect more than one user to the internet, you must have a router in place (Either software installed on a computer that acts as a router or a hardware based router like one you would get from D-link, SMC, Linksys,etc...). What happens is the router then takes the external IP given to you by your ISP and then clones your computer's mac address (allowing the company to only see your computer.) which allows the router to be seen as your computer (though you know that it's your router.). Now what happens now is the router is now assigned what ip and subnet mask settings your ip has assigned you, and will now act as your DHCP server (if you have enabled this option) and gateway. So now everyone you connect to the router will now get a internal ip (normally 192.168.0 1 - 192.168.0.255, though it varies from company to company) will now have access to an internal ip via the router internal network and resources as well as access to the internet.

Your router and network behind the router can not be seen by anyone other than you, or unless you allow a computer to be seen in the demilitarized zone (DMZ). What this does is it allows one machine to be seen as the primary holder of the external ip. So, say you have 10 pc's connected to the router, however you want a computer to act as a web server. Now instead of setting up port forwarders, you can place the web server in the demilitarized zone and it will be seen with both the internal and external ip. So you could connect to it if your external ip was 65.78.4.2, thats what people and the internet would see it was, while you would also see it as 192.168.0.44 in your internal network.

"In computer networks, a DMZ (demilitarized zone) is a computer host or small network inserted as a "neutral zone" between a company's private network and the outside public network. It prevents outside users from getting direct access to a server that has company data. (The term comes from the geographic buffer zone that was set up between North Korea and South Korea following the UN "police action" in the early 1950s.) A DMZ is an optional and more secure approach to a firewall and effectively acts as a proxy server as well.

In a typical DMZ configuration for a small company, a separate computer (or host in network terms) receives requests from users within the private network for access to Web sites or other companies accessible on the public network. The DMZ host then initiates sessions for these requests on the public network. However, the DMZ host is not able to initiate a session back into the private network. It can only forward packets that have already been requested.

Users of the public network outside the company can access only the DMZ host. The DMZ may typically also have the company's Web pages so these could be served to the outside world. However, the DMZ provides access to no other company data. In the event that an outside user penetrated the DMZ host's security, the Web pages might be corrupted but no other company information would be exposed. "

Hope that helps!