Home Network: NAT and TCP/IP

Home Network and NAT

• A home network consists of devices with private IP addresses (e.g., 192.168.0.2, 192.168.0.3, 192.168.0.4) that are not visible on the Internet.

• The home router (192.168.0.1) acts as a NAT (Network Address Translation) device that translates private IP addresses to a single public IP address (157.193.0.1) visible on the Internet.

NAT Translation

• When a device on the home network sends a request to a web server (172.217.17.131), the NAT device translates the private IP address to the public IP address.
• The translation is done using a translation table that maps the private IP addresses to the public IP address.

Internet Access

• The home router acts as a gateway to the Internet, allowing devices on the home network to access the Internet.
• The public IP address (157.193.0.1) is the only IP address visible on the Internet.

Network Components

• A switch is a network device that connects devices within the home network.
• The ISP (Internet Service Provider) network provides access to the Internet.### Port Forwarding
• Port forwarding allows access to a specific device or service within a private network from the internet.
• It requires configuration on the router to forward incoming requests to the correct device and port.

NAPT (Network Address and Port Translation)

• NAPT is a technique used to allow multiple devices to share a single public IP address.
• It translates both the IP address and the port number of incoming and outgoing network traffic.

Home Network Configuration

• A home network typically consists of a router, switch, and multiple devices connected to the router.
• The router is connected to the ISP network and has a public IP address.
• Each device on the home network has a private IP address.

NAT (Network Address Translation)

• NAT is a technique used to allow multiple devices to share a single public IP address.
• It translates the IP address of incoming and outgoing network traffic.
• NAT is used to conserve public IP addresses and improve security.

Translation Table

• A translation table is used to map private IP addresses and ports to public IP addresses and ports.
• The table is used by the router to forward incoming requests to the correct device and port.

Port Forwarding Examples

• Example 1: Port forwarding for a web server on port 80.
• Example 2: Port forwarding for two web servers on ports 80 and 8080.
• Example 3: Port forwarding for a web server on port 4001.

Real-World Examples

• Examples of port forwarding on home routers from TP-Link, Proximus, and Telenet are shown.
• These routers provide a web interface to configure port forwarding.

Nested NAT

• Nested NAT occurs when multiple NAT devices are used in a network.
• This can lead to complexity and difficulties in configuring port forwarding.

Home Network: NAT and NAPT

• NAT and NAPT are used in home networks to allow multiple devices to share a single public IP address.
• Examples of how NAT and NAPT are used in home networks are shown.