I need to be able to control my home Ubuntu server while im at work using my Ubuntu laptop over my phone's wifi hotspot. Speed isn't an issue, it's the same as my home DSL. Ive been using Chrome Remote Desktop in Windows but would rather not have to dual boot.
Before applying any of the following make sure you understand the security risk of exposing your system to the world at large.
If all you need is a terminal window, then you will only need a couple of things to setup.
First, you need to install and configure secure shell daemon (sshd) on your server - that is if it's not already installed.
Second, you need to have a static way of referring to your home network from the outside world. If your service provider has assigned a static IP on your connection, you just type
in a terminal window to connect to your server.
If you have a dynamic IP, then you can use one of the dynamic dns services available to get a meaningful name assigned to your address each time you connect to the internet. Check your router for support of dynDNS services and configure that. Then on a terminal type
to connect to your server.
Last, you will probably have to open port 22 (the default for ssh) on your firewall(s).
Again, make sure that you understand the security risks. A simple misconfiguration may leave your entire network exposed to the internet. This is no fun stuff.
I've been playing around with Amahi Home Server which has an OpenVPN module and also DDNS built right in. You'd install Amahi on your home machine (or another machine in your home) and you'd be able to use an OpenVPN client available for your phone, PC etc... and connect via SSH to your home machine(s)... works really well and is very easy to setup.. I've setup a VM running Amahi, but you could easily have this on your server, or on something as simple as a plug machine (their are instructions on the site).. it's free... http://www.amahi.org/