Fail2ban to avoid DOS attack on webserver

Install Fail2ban

Edit /etc/fail2ban/jail.conf

[http-get-dos]
enabled = true
port = http
filter = http-get-dos
logpath = /var/log/apache2/access.log
maxretry = 10
findtime = 5
action = iptables[name=HTTP, port=http, protocol=tcp]
bantime = 10


Edit /etc/fail2ban/filter.d/http-get-dos.conf

 [Definition]
failregex = ^<HOST>.*"GET

Restart Fail2ban

/etc/init.d/fail2ban restart

Check iptables you will see new chain

iptables -nvL

OUTPUT:-

Chain fail2ban-HTTP (1 references)
 pkts bytes target     prot opt in     out     source               destination        
    0     0 RETURN     all  --  *      *       0.0.0.0/0            0.0.0.0/0