I have and https site, which for one week receives a lot of strange requests just to main web site page (+ 2 js and 1 css files, but no images). From nginx logs it looks like:
193.151.188.114 - - [02/Feb/2021:13:09:32 +0100] "GET / HTTP/1.1" 200 4992 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:56.0) Gecko/20100101 Firefox/56.0"
193.151.188.114 - - [02/Feb/2021:13:09:33 +0100] "GET /js/jq.v.11.js HTTP/1.1" 200 36262 "https://website.com/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:56.0) Gecko/20100101 Firefox/56.0"
193.151.188.114 - - [02/Feb/2021:13:09:33 +0100] "GET /css/v.11.css HTTP/1.1" 200 44582 "https://website.com/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:56.0) Gecko/20100101 Firefox/56.0"
193.151.188.114 - - [02/Feb/2021:13:09:34 +0100] "GET /js/bootstrap.v.11.js HTTP/1.1" 200 52279 "https://website.com/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:56.0) Gecko/20100101 Firefox/56.0"
193.151.188.114 - - [02/Feb/2021:13:09:35 +0100] "GET / HTTP/1.1" 200 4992 "-" "Mozilla/5.0 (Windows NT 5.1; rv:52.0) Gecko/20100101 Firefox/52.0"
193.151.188.114 - - [02/Feb/2021:13:09:36 +0100] "GET / HTTP/1.1" 200 4992 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64; rv:56.0) Gecko/20100101 Firefox/56.0"
193.151.188.114 - - [02/Feb/2021:13:09:36 +0100] "GET / HTTP/1.1" 200 4992 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64; rv:56.0) Gecko/20100101 Firefox/56.0"
A lot of different IPs and seems like very old Firefox versions 56 and/or 52 even from the same IP address. This traffic is increasing from day to day and at the moment creates about 7gb per day. The server is working as normal at the moment.
What could be the reason? is there any way to prevent this?
Best regards.