How to prevent execessive scraping on Website on Ubuntu Server

Add rules as follows:

iptables -A INPUT -p tcp --syn --dport 80 -m connlimit\
 --connlimit-above 15 --connlimit-mask 32 -j REJECT \
 --reject-with tcp-reset 

This will reject connections above 15 from one source IP.

iptables -A INPUT -m state --state RELATED,ESTABLISHED \
-m limit --limit 150/second --limit-burst 160 -j ACCEPT  

In this 160 new connections (packets really) are allowed before the limit of 150 NEW connections (packets) per second is applied.

Note: if your server runs UFW (Uncomplicated Firewall), then you shouldn’t run the commands directly. Instead, you need to replace INPUT with ufw-before-input in each line and put the lines in the file /etc/ufw/before.rules. Afterwards, restart UFW using the following command:

sudo service ufw restart


Limit max connections per IP address and new connections per second with iptables – Unix & Linux Stack Exchange.