It is necessary to have a fixed IP to connect to a remote PC.
To connect to a computer, we need to know its IP address. But there are Dynamic DNS services that allow you to overcome this limitation and connect to a remote machine using a name of this type "votrelogin.dyndns.org".
The first step is to register on a Dynamic DNS service (dyndns.org, no-ip.com).
Install the small software client provided (This software send your IP address to the DNS server and automatically update it)
You only have to install the server of your choice on your computer (like http, ssh, vnc ...)