Linux comes with a host based firewall called Netfilter. The netfilter is a set of hooks inside the Linux kernel that allows kernel modules to register callback functions with the network stack. A registered callback function is then called back for every packet that traverses the respective hook within the network stack. This Linux based firewall is controlled by the program called iptables to handles filtering for IPv4, and ip6tables handles filtering for IPv6. I strongly recommend that you first read our quick tutorial that explains how to configure a host-based firewall called Netfilter (iptables) under CentOS / RHEL / Fedora / Redhat Enterprise Linux. If you are using Ubuntu/Debian Linux, see how to setup UFW for more info. This post lists most simple iptables solutions required by a new Linux user to secure his or her Linux operating system from intruders.
NIC teaming is nothing but combining or aggregating multiple network connections in parallel. This is done to increase throughput, and to provide redundancy in case one of the links fails or Ethernet card fails. The Linux kernel comes with the bounding driver for aggregating multiple network interfaces into a single logical interface called bond0. In this tutorial, I will explain how to setup bonding under Debian Linux server to aggregate multiple Ethernet devices into a single link, to get higher data rates and link failover.