ipset — Create IP sets for firewall rules. More information: <https://manned.org/ipset>.

Create an empty IP set which will contain IP addresses

ipset create {{set_name}} hash:ip

Destroy a specific IP set

ipset destroy {{set_name}}

Add an IP address to a specific set

ipset add {{set_name}} {{192.168.1.25}}

Delete a specific IP address from a set

ipset del {{set_name}} {{192.168.1.25}}

Save an IP set

ipset save {{set_name}} > {{path/to/ip_set}}