View Full Version : OT: IP addresses

08-31-2006, 01:04 PM
I have 4 computers networked behind a router and dsl modem. When someone "looks" at my system from the outside do they see one IP address for the network, or do they see each individual computers IP?

If each pc is identifiable by its own IP while on a lan, what happens when you ping my system? Which pc IP shows up on the trace?


08-31-2006, 01:12 PM
The only IP seen on the internet is the IP of the router. It performs a service called NAT (Network Address Translation). All data packets from the LAN are rewritten with the address of the router and when replies are received the router routes the data to the appropriate local IP address, which is why it is called a router. If your IP address is pinged the IP returned is the IP of the router, not the LAN addresses. The LAN addresses are from a reserved block of addresses that are not used or valid on the wide area network.

08-31-2006, 01:19 PM
Got it, thanks Evan.