For more stability your authorized_keys file can be setup to only settle for connections from specified IP addresses or hostnames. Environment that up is further than the scope of the information, but more details over the SSH authorized_keys file can be found at SSH Academy: Configuring authorized_keys for OpenSSH. https://bisnis-ibu-rumah-tangga-d94830.bloggerchest.com/28197040/the-smart-trick-of-createssh-that-no-one-is-discussing