Computer Networking · Intermediate level

Intermediate level · Module 2: DHCP, DNS and NAT · Lesson 3 of 3

NAT and Port Forwarding

Connect private networks to the internet and publish services carefully.

In this lesson you will

  • Explain NAT and PAT
  • Configure port forwarding safely

Key concepts

NATPATport forwardingexposure

The lesson

Network address translation (NAT) lets many private addresses share one public address; port address translation (PAT) tracks each connection by port.

Port forwarding sends incoming traffic on a port to an internal server, exposing that service to the internet.

Forward only what is necessary, never remote desktop or admin pages, and prefer a VPN or cloud service for remote access.

Step by step

  1. Observe NAT translations in the lab.
  2. Configure a port forward to a lab web server.
  3. Test from outside.
  4. Remove it and document the risk.

Practice activity

Configure NAT and a temporary port forward in the lab.

Expected result: Working NAT and a documented, removed port forward.

Check your understanding

  1. What does PAT allow?

    Show answer

    Many devices to share one public address using different ports.

  2. Which service should never be port-forwarded to the internet?

    Show answer

    Remote desktop.

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