I have a cloud based server. I followed this guide to configure its security : http://www.rubytreesoftware.com/resources/securely-setup-ubuntu-1404-server

The configuration of SSH is as follows:

# Edit or add the following configuration to sshd_config PermitRootLogin no PasswordAuthentication no X11Forwarding no AllowUsers andy deploy 

I authenticate with the remote server by adding my private key on my laptop to the authorised keys on the host.

My concern is, what happens if I loose my public key on the laptop. Am I locked out the server? What is best practice here - and how can I mitigate the risk of loosing my public key?

What happens if my public key changes? Also can I 'backup' my public key incase this happens? I assume no because its a key pair specific to the machine but worthwhile checking.

The firewall being used is ufw and is configured like so :

# configure ufw sudo ufw logging on sudo ufw allow ssh sudo ufw allow www 

If there is something else I should have done to secure this server which delivers a web application please let me know what I've missed. Any good articles on securing servers which are cloud based and serve public applications would be highly appreciated.

Please help!

I have a cloud based server. I followed this guide to configure its security : http://www.rubytreesoftware.com/resources/securely-setup-ubuntu-1404-server

The configuration of SSH is as follows:

# Edit or add the following configuration to sshd_config PermitRootLogin no PasswordAuthentication no X11Forwarding no AllowUsers andy deploy 

I authenticate with the remote server by adding my private key on my laptop to the authorised keys on the host.

My concern is, what happens if I loose my public key on the laptop. Am I locked out the server? What is best practice here - and how can I mitigate the risk of loosing my public key?

What happens if my public key changes? Also can I 'backup' my public key incase this happens? I assume no because its a key pair specific to the machine but worthwhile checking.

The firewall being used is ufw and is configured like so :

# configure ufw sudo ufw logging on sudo ufw allow ssh sudo ufw allow www 

If there is something else I should have done to secure this server which delivers a web application please let me know what I've missed. Any good articles on securing servers which are cloud based and serve public applications would be highly appreciated.