Training Trains Internship
Student login
← Network Security learning path
Network Security · Module 4 of 10

Firewalls

Filter traffic with firewalls.

📖 Key ideas

  1. Firewalls allow or block traffic using rules.
  2. Packet-filtering: by IP, port, protocol.
  3. Stateful firewalls track connections.
  4. Next-generation firewalls (NGFW) inspect applications and threats.
  5. Default deny: block everything, allow only what is needed.
💡 Real-life example: A firewall is a security guard at the gate checking every visitor against a list.
FirewallFilters network traffic
Stateful inspectionTracks connection state
NGFWNext-generation firewall
Default denyBlock unless explicitly allowed