One-to-One NAT Explained

One-to-One NAT, also known as Static NAT, is a network address translation technique that maps a single private IP address to a single public IP address. This method ensures that the same private IP address always translates to the same public IP address, providing a consistent external identity for devices on a local network.

Key Concepts

1. Static Mapping

Static mapping involves creating a permanent, unchanging relationship between a private IP address and a public IP address. This ensures that any traffic originating from the private IP address is always translated to the same public IP address.

2. Consistent External Identity

One-to-One NAT provides a consistent external identity for devices on the local network. This is particularly useful for servers that need to be accessible from the internet using a fixed public IP address.

3. Configuration Steps

Configuring One-to-One NAT involves specifying the private IP address and the corresponding public IP address. This configuration is typically done on the router or firewall that connects the local network to the internet.

Detailed Explanation

Static Mapping

Static mapping ensures that a specific private IP address is always translated to the same public IP address. This is achieved by creating a static NAT rule that maps the private IP address to the public IP address. For example, to map the private IP address 192.168.1.10 to the public IP address 203.0.113.5, you would use the following command on a MikroTik router:

Consistent External Identity

One-to-One NAT ensures that devices on the local network have a consistent external identity. This is particularly useful for servers that need to be accessible from the internet using a fixed public IP address. For example, a web server with the private IP address 192.168.1.20 can be configured to use the public IP address 203.0.113.10, ensuring that all incoming traffic to 203.0.113.10 is directed to the web server.

Configuration Steps

To configure One-to-One NAT on a MikroTik router, follow these steps:

1. Navigate to the IP Firewall NAT menu.
2. Create a new NAT rule with the chain set to srcnat.
3. Set the action to netmap.
4. Specify the private IP address in the src-address field.
5. Specify the public IP address in the to-address field.
6. Apply the rule to enable One-to-One NAT.

Examples and Analogies

Example: Static Mapping

Think of static mapping as a permanent name tag. Just as a name tag identifies a person at a conference, static mapping identifies a specific device on the internet with a consistent public IP address.

Example: Consistent External Identity

Consider a business with a main office that needs to be accessible from the internet. By using One-to-One NAT, the main office (private IP address) is always identified by the same public IP address, making it easy for clients to connect.

Example: Configuration Steps

Imagine configuring One-to-One NAT as setting up a permanent address book entry. Just as you would add a contact to your address book with a specific name and address, you configure the router to map a private IP address to a public IP address, ensuring that the mapping is permanent and consistent.

By mastering One-to-One NAT, you can ensure that devices on your local network have a consistent external identity, making it easier to manage and secure your network.