I'm able to connect to my server through my Windows 8.1 using FileZilla and PuTTy perfectly fine also using andFTP while I'm on the local network, how ever that's not the case otherwise. I've tried connecting the same way using other networks and that doesn't work at all. I've made sure numerous times that the credentials are correct. I'm new to Linux in general and would be very appreciative if someone can explain in detail the steps to take so I'm able to connect to my new server remotely from anywhere.
Okay. Here's the basics of networking and your problem:
You have a local network behind your router, and your brother has a local network behind his. Each one of your local networks are, well, local to you. You are completely isolated from each other. Your server's IP address is 10.0.0.17, right? So if your brother tries to ping that IP, he'll be trying to ping a machine on his network that has that IP. But since he doesn't, he gets a "host not found" error.
If you want to make him be able to connect to your server from outside your network, you'll have to do something on your router called "port forwarding". Right now, your router has a public IP address, say 22.214.171.124. Now this IP, your brother can probably reach, because it's a public IP address. What you'll have to do is go into your router and tell it "hey, if someone reaches you at port 22 (so if someone reaches 126.96.36.199 on port 22), forward that connection internally to 10.0.0.17 on port 22". So you'd be telling your router to forward that connection to your server. That's what "port forwarding" is, and that's what you have to do to make your server accessible from the internet. When you do this, your brother can connect to 188.8.131.52 using SSH and it should work.
- This all depends on whether your router supports this, but it most likely does. Read this for more information on port forwarding: http://portforward.com/help/portforwarding.htm.
- Your server is not exposed to the internet, the outside world. The outside world is pretty dark, so you have to make sure that you have strong passwords and an up-to-date server (yup, that's why people say we have to update to be secure).
In any case, your problem is not Ubuntu related, and AskUbuntu is certainly not the place to find out how to do port forwarding on your router.