How does Windows Remote Desktop Connection know which computer to connect to?

Question

How does Windows Remote Desktop connection work? An IP address is used to connect to the computer but....how can that IP be accessed from anywhere? If, for example, the IP address is 192.168.1.55, there MUST be another 192.168.1.55 somewhere else in the world. How does Remote Desktop know which one to connect to?

Thanks so much

edit: and if i had been using remote desktop for a while and then it quite suddenly doesn't work, what should i check? the computer can be remote connected with a LAN computer however.......how should i even start to solve this problem?

Answer 1

192.168.1.55 falls in the private IP range:

10.0.0.0-10.255.255.255
172.16.0.0-172.31.255.255
192.168.0.0-192.168.255.255

These are all the private IP ranges. Simply put, these packets will never leave your local network, and are non-routable out on the public internet. So, yes, there are thousands (probably millions) 192.186.1.55s, but it always connects to the local one (it's the computer/router's only option).

Answer 2

The 192.168.X.X is used for internal (private) use only. That means it is used in your own network and there can easily be a duplicate of this in every network in the world. Usually your router keeps this "internally".

Imagine you're in a country and your router is the country's border. There can be only one person with social security number (or any other unique property) 123 in your country but beyond your borders (router) there could easily be another person with social security number 123 since it's a different country with a different administration.

To distinguish between person A with 123 and person B with 123, they invented global IP-addresses. These are unique and can be compared to a physical address. Every internet connection (usually shared by several PC's) has one unique global IP-address. This IP-address is used when connecting to PC's outside your own "country" (network).

Answer 3

how can that IP be accessed from anywhere?

As others have described, it can't be. If you aren't on the same network as the machine you want to RDP into, that machine needs to have a routable - i.e., public - IP address, or, as in this case, it must be connected to a router that has, and that router would have had to have been configured to forward the RDP port (3389, by default) to (in this case) 192.168.1.55. You would RDP to the public address.

Answer 4

Everyone connecting to the internet will be assigned a static IP ie the router/modem will get a static IP on its WAN interface (in case of home connections).

Now the router will have a DHCP server which will assign you a private IP like 192.168.1.55.

Now for you to access the internet the private IP will be mapped to the static IP of the router and then it will go to the internet. This is called NATTING = mapping of private IP to static IP. Same will be the case of any other users on LAN.

Now when you want rdp to work the firewall in the router should allow rdp connections. So a rdp packet from your computer will be mapped with the static IP and sent to the destination where another natting will take place.

Hope you are clear.