General Objective of the Course

This course aims overall to provide a deep and practical understanding of NAT configuration and its application in ISP environments.

It will focus on teaching students how to efficiently assign public and private IP addresses, configure routers for different networking needs, implement advanced routing techniques, and manage network traffic optimally.

In addition, key topics will be addressed such as the rport forwarding, NAT Hairpin, and the public IP management, ensuring that participants acquire the skills necessary to manage and optimize complex networks in an ISP context.

This knowledge will be vital for those seeking to improve network infrastructure and service quality in large, constantly evolving organizations.

Objectives by Chapter

1. How to assign a non-manageable public IP with port forwarding

Assign a Non-Manageable Public IP to Clients

You will learn how to assign an unmanageable public IP to a client using NAT. This allows the client to access their edge router and all their network traffic to be masked through this public IP, thus simplifying network management.

Configuration and Effective Use of NAT on the Edge Router

You will understand the need to correctly configure the public IPs provided by the Internet providers and the NAT rules on the edge router. This includes the use of NAT 1 to 1 for bind each public IP to a specific private IP, ensuring a unique and efficient correspondence between both.

Implementation of Masking and External Access Rules

You will learn how to configure two types of rules on the router: one for masking the client's network (using the Chain srcnat) and another to allow external access to the public IP assigned to the client (through the Chain Destination NAT), highlighting the importance of the correct location of these rules in the router configuration.

Enabling both Internal and External Network Access

You will study how to configure an additional rule of Hairpin NAT to allow access to the client's network both inside and outside of it using the same public IP. This ensures that traffic destined for a public IP from the client's private network can be appropriately redirected, thus facilitating comprehensive and unrestricted access.

2. How to assign a non-manageable public IP through NAT

Unmanageable Public IP Assignment for Remote Access

The main objective is to teach how to assign an unmanageable public IP to a client to allow remote access to their router. This is crucial for residential customers who need to connect to your network from external locations.

NAT Configuration on the Edge Router

The video aims to explain the configuration of Network Address Translation (NAT) on the edge router, using public IP addresses provided by Internet providers. This step is essential to manage network traffic and enable efficient remote access.

Implementation of Port Forwarding for Specific Traffic Direction

A key objective is to detail the process of configuring Port Forwarding on the router. This technique is important for directing Internet traffic to specific devices within a private network, using the TCP protocol and specific ports for remote access.

Enabling Internal and External Access via Hairpin NAT

The video seeks to demonstrate how to implement an additional NAT rule, known as Hairpin NAT, to allow access to the public IP address both inside and outside the client's private network. This aspect is essential to guarantee comprehensive and unrestricted access to the client's network through the assigned public IP.

3. How to assign routable (manageable) public IP addresses to a client

Need for Manageable Public IP Addresses:

The demand from ISP clients to obtain managed or routed public IP addresses is highlighted, allowing them to configure their own networks and assign public addresses to their users.

ISP Network Preparation and Configuration:

It details the necessary preparation, such as receiving a segment of public IP addresses from the provider and configuring these addresses on the ISP's network. The importance of proper subnetting of the public IP address segment is emphasized, such as dividing a /24 segment into /28 or /29 subnets, depending on customer needs.

Route and NAT Configuration on ISP Routers:

The video guides you through configuring routing across the ISP's network, including configuring static routes and NAT settings on the edge router and other devices. Shows how to configure routes so that traffic from certain IP segments passes specifically through a particular Internet provider and how to prevent these segments from being masked.

Implementation on the Client Network:

Finally, we describe how to implement these changes on the client's network, including configuring public IP addresses on client devices and adjusting NAT rules to allow effective use of public IP addresses. Tests are performed to confirm that clients can access and be reachable through their new public IP addresses.