SSH is secure shell. The remote program to control other machine from network. Even we can combine it through internet. SSH uses secure channel that won’t be easily to be hacked. It uses port 22 for standart. But you may change the port so other people won’t guess the port. Although in Linux you can find out which port open in the network. We won’t tell you about it right now. Just the appliance of SSH.
Let say that we will connect two machine with this SSH. One machine is the server (just the name not real server) and other is the client or the remote. Both of them need to be installed SSH. You can check it in the console. Ubuntu or slackware has the same way. Just type ssh. If there’s ssh program it will show you some list of option. If there isn’t it will go error. In this case you need to install it.
You can download openssh from here and install it to slackware.
In Ubuntu simply type this
and Ubuntu will do the installation automatically.
Then you can edit the configuration if you want to especially in server machine.
Find a line that wrote Port 22 then change to any port you want. Or you want to change other setting. But I will not tell your further about that, it is very risky too.
You may restart both machines and try it by typing
Givi it a try