Introduction If you encounter such error, it means that the CONFIG_NETFILTER module was not complied in your kernel. All VPS (virtual private server) that I owned from DigitalOcean, AWS, Google Cloud and other lesser-known host providers have it by default...
How to Secure Server with Firewall using iptables
iptables is a command-line firewall utility that allows a system administrator to configure the IP packet filter rules made possible by the Netfilter modules complied into the Linux Kernel. The rules are kept to a bare minimum on the firewall…