To create ip set called hacker_ips

$ sudo ipset -N hacker_ips iphash

To add IP address  to the hacker_ips ipset

$ sudo ipset -A hacker_ips 172.122.150.22

$ iptables -A INPUT -m set --set hacker_ips src -j DROP

To create ipset named my_blacklist 
$ sudo ipset create my_blacklist hash:ip hashsize 4096

To drop all ip address stored in ipset called my_blacklist

$ sudo iptables -A INPUT -m set --set my_blacklist src -j DROP

To add IP address in ipset my_blacklist

$ sudo ipset add my_blacklist 192.168.100.22

$ sudo ipset add my_blacklist 172.122.150.22

$ sudo ipset add my_blacklist 192.168.100.10/24

To make ipset persistent across reboots

$ sudo ipset save > /etc/ipset.conf

To view the sets

$ sudo ipset -L

To delete a set named hacker_blacklist

$ sudo ipset -X hacker_blacklist

To delete all sets

$ sudo ipset destroy

regards,

T.Dhanasekar