Firewalls

• Firewall


  A device or software that monitors networks and filters messages sent over these networks based on certain rules determined by the network owner
• The name "firewall" comes from the analogy of a physical firewall in a house, which stops a fire from spreading between rooms
• Firewall


  • Stops malicious messages, such as denial of service messages or messages containing malware, from spreading from the internet to internal networks
• How a firewall works

  1. Checks messages against a blacklist or whitelist of allowed/blocked websites, countries, etc.

  2. Blocks messages that do not adhere to the rules
• Firewall setup


  • Laptop connected to firewall, connected to router
  • Firewall can be a standalone hardware device or software on a computer
• Attacker tries to send malware

  Firewall blocks the message from reaching the computer
• Software firewall


  • More common than hardware firewall
  • Runs on the computer, so attacker can still reach the computer if the firewall is breached
• Hardware firewall


  • Safer than software firewall as attacker cannot directly reach the computer
  • More expensive and harder to set up than software firewall