The process of protection against attacks are similar to what one does on physical servers. D-DoS attacks are mainly to disrupt a business from functioning. The attacks generally are planned and done by flooding the website with traffic from different sources. On a VPS hosting
you can configure the firewall and close all entry ports and allowing only http, https and ssh users. Another way of attack is the BruteForce attack and to prevent it you are advised to use lengthy passwords of about 30 characters and keep changing it frequently at least once in 90 days.