Network Address Translation (NAT) is a method used in computer networking to modify network address information in packet headers while in transit through a router or firewall. The primary purpose of NAT is to conserve IP addresses by allowing multiple devices within a private network to share a single public IP address for communication with devices outside the private network, such as on the internet.

Here's a breakdown of NAT's functionality:

• Address Translation: NAT translates private IP addresses used within a local network into public IP addresses used on the internet and vice versa. This allows devices with private IP addresses to communicate with devices outside the local network.
• IP Address Conservation: NAT helps conserve public IP addresses. Instead of assigning a unique public IP address to each device within a private network, NAT allows multiple devices to share a single public IP address.
• Security: NAT acts as a firewall by hiding the internal network structure and providing a level of security. External entities see only the public IP address, making it more difficult for attackers to directly access devices within the private network.
• Port Address Translation (PAT): A specific type of NAT, PAT, allows multiple devices within a private network to share a single public IP address by using different port numbers to distinguish between the internal devices. This is also known as NAT overload.

NAT operates at the network layer (Layer 3) of the OSI model. It is commonly used in home and small office networks, as well as in large enterprise networks, to provide internet connectivity while preserving IP address resources.

In this tutorial, we will show you the configuration of NAT on huawei device

# Enter system view

 Router# system-view 

# Configure NAT

 Router# nat 
Router-nat# nat address-group 1 1.1.1.1 mask 255.255.255.0
Router-nat# nat address-group 2 2.2.2.2 mask 255.255.255.0
Router-nat# quit 

# Create an ACL to define traffic to be translated

Router# acl 2000
Router-acl-adv-2000# rule 5 permit source  
Router-acl-adv-2000# quit 

# Apply the ACL to specify the traffic to be translated

Router# interface 
Router-interface# nat outbound 2000 address-group 1 pool-id 1 

# Optionally, configure NAT for incoming traffic (port forwarding)

Router# nat protocol tcp global 1.1.1.1 inside inside_ip service outside_port inside_port