nginx UserAgent Blacklist, so i found this UserAgent on different system.

iptables.sh

for ip in $(grep -ri Baidu             /var/log/nginx/access.log | cut -f1 -d' ' | sort | uniq); do echo $ip && iptables -I INPUT -s $ip -j DROP; done
for ip in $(grep -ri 200please         /var/log/nginx/access.log | cut -f1 -d' ' | sort | uniq); do echo $ip && iptables -I INPUT -s $ip -j DROP; done
for ip in $(grep -ri majestic12        /var/log/nginx/access.log | cut -f1 -d' ' | sort | uniq); do echo $ip && iptables -I INPUT -s $ip -j DROP; done
for ip in $(grep -ri opensiteexplorer  /var/log/nginx/access.log | cut -f1 -d' ' | sort | uniq); do echo $ip && iptables -I INPUT -s $ip -j DROP; done
for ip in $(grep -ri seokicks          /var/log/nginx/access.log | cut -f1 -d' ' | sort | uniq); do echo $ip && iptables -I INPUT -s $ip -j DROP; done

nginx.conf

if ($http_user_agent ~* (Firefox/0.10.1) ) {
   return 403;
}

if ($http_user_agent ~* (BLEXBot|Baiduspider|AhrefsBot|Moreoverbot|infohelfer|FairShare|YandexBot|Ezooms|Spider|Illu|seokicks|MJ12bot|200please|MojeekBot|opensiteexplorer) ) {
   return 403;
}