In computer networks, NAT provides connectivity between devices on local and external networks. There is also a Static NAT type. This securely maps internal addresses to external ones.
In this guide, I will tell you exactly what Static NAT is and how it works. In addition to its configuration, I will explain its methods and its importance in network security.
What is Static NAT?
It assigns one-to-one internal and external addresses. This type allows external devices to connect to internal devices via the public one. For example, you can access an internal web server from an external network. You do this by assigning a specific internal number.
With this method, you can connect a computer or device on the local network to the Internet. You can also map a device with a private IP address to a single public number.
You can also use this method manually to configure a specific device. However, I recommend that you apply the NAT system in different scenarios in more extensive network topologies. Plus, you can hide the IP block to increase LAN security.
In Cisco or other router models, you can use CLI or GUI to configure Network Address Translation. Plus, you can examine the working logic of the address mapping system in general from the image below.
In fixed NAT, it works in the same way as the structure in the image above. However, routes are added manually. In such a case, a static conversion is applied to a computer that will access the external network from the local one.
How Does Static NAT Work?
To better understand the working logic of this, you can create and configure a topology as in the image below with the Packet Tracer software.
In the above translations, the computer with the address 192.168.10.10 accesses the Internet. However, it does this by converting to a Global IP address assigned by the ISP.
If the ISP allocates more than one address, you need to implement Dynamic NAT on the Router. Instead, organizations with a single Public IP can only use the fixed system. Thus, they can only expose specific devices in their local network to the Internet.
Also, let’s say there is no NAT record for a second computer in the network topology. At this point, of course, this PC definitely cannot access the Internet. Therefore, it is necessary to add a fixed record for this device.
After all, in statistics, Inside Local refers to private LANs. On the other hand, we express the term Inside Global as a global network.
Differences Between Dynamic and Static NAT
Both are methods we use to translate Internet addresses. Both methods serve a similar purpose but work differently.
| Feature | Dynamic | Static |
|---|---|---|
| Definition | It maps private IP addresses to public addresses. | It provides the permanent mapping between private and public IP addresses. |
| IP Mapping | When a private IP address communicates with an external one, it selects a public number from the pool. It activates the mapping process for the duration of the communication and then returns it to the pool. | It always translates the private IP address to the same public address. |
| Areas of Use | We typically use it for devices that obtain IP addresses from dynamic pools. | We often use it for services that require constant access, such as web servers. |
- Main Differences
- Dynamic architecture allows many private IPs to share a small number of public IPs by selecting numbers from a pool.
- Static architecture increases consistency by maintaining a fixed mapping between private and public IPs.
- Advantages and Disadvantages
- The dynamic system provides more efficient address usage. However, we run into problems when the public address pool is exhausted.
- In a static system, we provide consistent access to specific resources. However, it may increase IP usage for resources that do not require permanent access.
Which One Should I Choose When?
When deciding whether to use Dynamic or Static, you should check your internal resources. In other words, you should consider the access requirements of your devices.
If you have servers that require constant access, fixed is suitable for you. Otherwise, I recommend you choose it for your general Internet access.
In short, Dynamic and Static IP mapping systems offer different methods. By knowing these differences, you will have efficient and secure network infrastructures. Thus, you can make conscious choices according to internal and external access needs.
Configuration ⇒ Video
Below, I have created a Static NAT project for you using a network topology using Packet Tracer. Here is our video tutorial showing how to set it up. You can also show your support by subscribing to our YouTube channel for more networking experiences!
Conclusion
Let me make it simple: Static Network Address Translation (NAT) is a powerful tool. With this method, you get a secure mapping between internal and external addresses.
Understanding the details of Static NAT is vital in your networking experience. Therefore, you can make your infrastructure more secure and manually configure specific devices. In short, it is simple to control external access.
TolgaBagci
Hi, I'm Tolga, a computer expert with 20 years of experience. I help fix computer issues with things like hardware, systems, networks, virtualization, servers, and operating systems. Check out my website for helpful info, and feel free to ask me anything. Keep yourself in the loop about the newest technologies!
