[Treborika]

You can achieve this by: keeping all software up to date including the operating system, web server and any applications running on the server.

[raaman]

I think this should be the concern of the website owners than a commoner like you and me.

[mrki444]

Add Cloudflare for preventing DDOS attack. Currently offer best service in that area.

[Mika]

Without knowing what kinds of attacks you are talking about, I cannot be specific on my answer. A website can be attacked in different ways.