I have set up a remote ssh server on the cloud. I am newb at these things and have managed to bypass the required firewall using SSH. Now I plan on giving the access to only 2 more friends of mine so as to share the costs of data transfer so that only 3 users at max can connect and only the friends. So my question is that How can I achieve this?
The server is running Ubuntu Linux. Also, the college has a static IP so each one gets a proxified IP. Is there any way that I can do MAC filtering over the Server?
Also, if you insist on using SSH KEYS, then would they restrict access if someone just copied the key and used it? Please also suggest a way, if the MAC spoofing could be bypassed?