1.
vim /etc/apache2/apache2.conf
2.
<Directory /var/www/html>
Order Deny,Allow
Deny from all
Allow from 103.21.244.0/22 103.22.200.0/22 103.31.4.0/22 \
104.16.0.0/13 104.24.0.0/14 108.162.192.0/18 \
131.0.72.0/22 141.101.64.0/18 162.158.0.0/15 \
172.64.0.0/13 173.245.48.0/20 188.114.96.0/20 \
190.93.240.0/20 197.234.240.0/22 198.41.128.0/17
Require ip 2400:cb00::/32 2606:4700::/32 2803:f800::/32 \
2405:b500::/32 2405:8100::/32 2a06:98c0::/29 2c0f:f248::/32
Require all granted
</Directory>
3.
sudo systemctl restart apache2