Networking – Firewall


Firewall, typically in network, is a system that monitors and controls the incoming and outgoing network traffic based on predetermined security rules. Firewall establishes a barrier between a trusted, secure internal network and another outside network, such as internet, that is assumed insecure or not trusted. Often often categorized as either network firewalls or host-based firewalls.

This page is a metapage. It means deeper and more focused article will be written in other place and their entry will be indexed here. Browse following catalog to search what you want.

Table of Content

  1. Network Firewalls
    1. Use OS’ Firewall Module
    2. Use Firewall OS
    3. Use Firewall Hardware
  2. Host-Based Firewalls
  3. Firewall Generation


  1. Server Hardware
  2. Access Control List
  3. Distributed Firewall for Network

Network Firewalls

A software appliance running on general purpose hardware or hardware-based firewall computer appliance that filter traffic between two or more networks. Routers that pass data between networks contain firewall components and can often perform basic routing functions as well.

To obtain a network-firewall, we can:

  1. Use network capable operating system such as Linux and BSD and add firewall modules in their respective way. In most case, firewall is installed by default.
  2. Install specialized OS for firewall.
  3. Buy firewall in hardware solution.

[x] Use OS’s Firewall Module


  • IPTables


  • IPFW

[x] Use Firewall OS

For complete list, you can visit wikipedia on subject router and firewall distribution


  • Installation
  • Configuration
  • Case


  • Installation
  • Configuration
  • Case

[x] Use Firewall Hardware

Various firewall hardware exists. I only write firewalls which I had interact with.

Host-Based Firewalls

A layer of software on one host that controls network traffic in and out of the machine.