how do You block IP address on Linux?


One way to do it on Linux is to execute command:

/sbin/iptables -I INPUT -s IPHERE -j DROP
In case one is using Linux server as a proxy (example OpenVPN) one may need to modify the command little bit to become:

/sbin/iptables -I FORWARD -s IPHERE -j DROP
In case iptables command is not found, you may try command "which iptables", if iptables is not found, you may need to use different way to block IP.