Hello.
How routing happening a network? In a network with an Internet gateway and lot of computers, How an external computer find me for connecting?
For example, my Network with 200 computers just have an static Internet IP and when I share my IP with other person in the world and he ssh to me, How him ssh understand that must connect to my Linux box and not other Linux PC in the network?

Thank you.

Talk to your network administrator and ask them if your system can be given a publicly visible address. If it cannot, which would purely be a matter of their policy, then it cannot. Otherwise, they'll configure it and advise you as to what the system host name would appear as to an outside system.

A full explanation of routing is a lengthy explanation which I'm not going to cover and I don't suggest someone else do that either. You'll likely have a lengthy list of questions. Either you have a network administrator or you don't. If you're configuring this on your own, then lookup the instructions for your particular router.

Internet IPs have to be unique. Another person in the world finds you because the IP range is assigned to whoever provides you internet service (e.g. your ISP for home users and small commercial users, your carrier for larger commercial purposes). They in turn assign you an IP (or a range of IPs) from those they own.

Internal IPs can be duplicated outside your network by others (e.g. 10.x.x.x and/or 192.x.x.x are used by most organizations internally (or even your home router). It might be exactly the same internal IP as hundreds of others use on their internal network but it isn't a problem because these IPs are not allocated on the internet.

On occasion you need someone in the world to reach something that has an "internal" IP but they reach it on an "internet" IP and that is using done by doing something called address translation (e.g. NAT) in whatever device you have on the internet (router) that tells any traffic reaching it on the "internet" IP to go to your "internal" IP.

Additionally DNS is used for associating names with IPs on the internet and that is a whole subject itself.

This is a fairly complicated subject and not one you're going to really get by asking a global question such as you did. You can look for networking tutorials online and start working your way through them. Alternatively you usually don't need to know the entire structure of the internet to solve a specific question. If you have a specific issue you're trying to troubleshoot asking a question directly about that issue would likely get you a better answer.

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If you want to learn how routing works, this is the best tutorial I've seen. Don't be fooled by the Web 1.0 appearance; it's clearly written and easy to understand. When I first read it, I was completely new to the world of networking and it helped me immensely.

When I first stumbled over it, it was on an *.edu site (University of Colorado in Boulder, Colorado, USA, I think). My guess is that the author retired or changed professions and just ported the existing tutorial to a personal site.

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