CentOS completely disables access from an IP address

Completely prohibit access to an IP address: # The command to shield a single IP address is the iptables-IINPUT-s123.45.6.7-jDROP # block the entire segment from 123.0.0.1 to 123.255.2

Completely prohibit access from an IP address:

1. # The command to shield a single IP address is

   Iptables-I INPUT-s 123.45.6.7-j DROP

    

2. # The Command for sealing the entire segment from 123.0.0.1 to 123.20.255.254

   Iptables-I INPUT-s 123.0.0.0/8-j DROP

    

3. # An IP address segment is a command from 123.45.0.1 to 123.45.255.254.

   Iptables-I INPUT-s 124.45.0.0/16-j DROP

    

4. # The Command from 123.45.6.1 to 123.45.6.254 is

   Iptables-I INPUT-s 123.45.6.0/24-j DROP