A browser uses the DNS system to convert a domain name into an ip address. But once it has the the ip address how does it know where the server is located and reach the server to download the site?

The point of an ip address is that each one is unique. It’s not unlike an address on an envelope. How does the mail know where to go? There is only one possibility.

An IP address defines both the “name” of the destination and to some extent “route” to get there. You ask other computers ever more specifically “do you know this computer? Do you know another computer that might?” Since the address is chunked into big blocks, you eventually get routed upstream towards computers that can answer either or both of those questions because they know not that specific computer, but computers that share whole chunks of its address.

it doesn’t need to know the physical location. it just goes to an address. the internets have gps.

The computer doesn’t know where the IP address is located. It just knows where to send that packet.

It has a table in its memory that indicates where to send packets. The table will show that (for instance) 192.168.0.* is the local network, and that everything else is to be sent to the router at 192.168.0.1. So it sees that the packet goes to 67.207.146.191, and hands it over to the computer at 192.168.0.1.

That computer also has a routing table, and probably (since 192.168.* is a private IP range) a translation table. It sees that everything that’s not in 192.168.* goes to its upstream router. Each router looks up its own routing table, and then sends the packet in the right direction.

At some point, it will reach a top-level router that knows that 67.* goes to this router, and then that one knows that 67.200.* through 67.208.* goes to that router, and then that one knows that 67.207.146 is this particular data center, and then 67.207.146.191 is that particular machine.

http://www.bing.com/search?q=how+do+routing+tables+work