Introduction to port forwarding

• port forwarding is essential component in connecting applications and services to the internet.
• without it the services will only be available in the same network.
• Take the network below as an example. Within this network, the server with an IP address of "192.168.1.10" runs a webserver on port 80. Only the two other computers on this network will be able to access it (this is known as an intranet).

• If the administrator wanted the website to be accessible to the public (using the Internet), they would have to implement port forwarding, like in the diagram below:

• Now the Network #2 will be able to access the web server running in the Network #1 with the help of this port forwarding.
• Port forwarding is configured at the router of the network

Firewall 101

• Firewall is device within a network responsible for determining what traffic is allowed to enter and exit the network.
• It is like border security for a network.
• Administrator can configure what traffic could enter or exit the network based on the factors such as:
  • Where is the traffic coming from?
  • Where is the traffic going to?
  • What port is the traffic for?
  • What protocol the traffic use.
• Firewalls perform packet inspection to determine the answers to these questions.
• Firewall comes in various sizes and shapes.
• It can be a dedicated piece of hardware or just a software like snort, or ufw
• Primarily firewalls are classified into two: