How to block that ddos atack

Hello, i have a problem with my server, beacuse I will get a DDos layer 7 atack on my website.

In apache live log, atack look like:

34.243.184.40 - - [18/Aug/2019:05:20:41 -0400] "GET /about/ HTTP/1.1" 200 9273 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.99 Safari/537.36"

How can i block it?

I suggest you to use CSF Firewall and also please enable Mod Security. By have those two enabled, you may avoid DDos Attacks.