I'm thinking that blocking access to the SSH port to allow for my country only is an obvious step, but I can't see a practical way to do this.
I'm in the UK if it matters. I have full access to the Ubuntu server. The server is a remote cloud-based server.
This seems too easy and I can't see how it can work: http://eminasif.wordpress.com/2014/01/14/how-to-restrict-server-ssh-access-or-any-port-only-for-specific-country-in-csf/
This shows a load of IPs but I can't see how I can transfer that to anything usable/practical: http://www.nirsoft.net/countryip/gb.html
In fact, only one office of people will ever need access (nobody is remote). I'm reluctant to set the current IP address we use when connecting though as it seems to change every 6 months.
I do have other good security practices in place - disable root login, high-bit encryption keys etc. but this seems an obvious extra step.
Is this worth the hassle? Is there a reliable way to do it?