Remote VPN back home network behind CGNAT or Private IP

 

The Purpose of Remote VPN, CGNAT, and Private IP

Introduction

With the increasing number of people working from home, remote VPN has become an essential tool for many businesses to ensure their employees can access company resources securely. However, there are some technical terms that are often associated with VPN, such as CGNAT and private IP, that may be confusing for non-technical individuals. In this blog post, we will discuss the purpose of remote VPN, CGNAT, and private IP.

Remote VPN

Remote VPN, or Virtual Private Network, is a technology that enables users to securely connect to a private network over the internet. The primary purpose of remote VPN is to establish a secure communication channel between the user's device and the company's network. This is achieved by encrypting the data that is transmitted between the two ends of the connection, making it difficult for unauthorized individuals to intercept or access the data.

Remote VPN is particularly important for businesses that have employees working remotely, as it allows them to access company resources, such as files and applications, as if they were physically present in the office. Additionally, remote VPN can also be used to bypass geo-restrictions and access content that may be blocked in certain regions.

CGNAT

CGNAT, or Carrier-Grade NAT, is a technology used by internet service providers (ISPs) to conserve IPv4 addresses. IPv4 addresses are the unique numerical identifiers assigned to every device connected to the internet. As the number of devices connected to the internet has increased, the available pool of IPv4 addresses has dwindled. CGNAT helps alleviate this scarcity by allowing multiple devices to share a single public IPv4 address.

However, CGNAT can cause issues for remote VPN connections, as it can interfere with the ability to establish a direct connection between the user's device and the company's network. This can result in connection issues, slow speeds, and other performance problems.

Private IP

A private IP address is an IP address that is not routable on the internet and is used for internal network communication. Private IP addresses are assigned to devices on a local area network (LAN) and are not accessible from outside the network.

When a user connects to a remote VPN, their device is assigned a private IP address on the company's network. This allows the user to access company resources as if they were physically present in the office, without the need for a public IP address.

Connecting CGNAT + Private IP + Remote VPN relationship

When an ISP uses CGNAT, it can result in multiple devices sharing a single public IP address. This can cause issues when attempting to establish a secure remote VPN connection, as the private IP address assigned to the user's device may not be unique and could be shared with other devices on the same local network. This can make it difficult for the VPN server to identify and route traffic to the correct device, resulting in connection issues and other performance problems. As a result, remote VPN connections behind CGNAT can be challenging, and may require additional configuration and troubleshooting to ensure a stable and secure connection.

Remote VPN using port forwarding and DDNS won't work behind CGNAT

Another method for establishing a remote VPN connection is by using port forwarding and a Dynamic DNS (DDNS) service. Port forwarding involves forwarding specific ports on the router to the VPN server, allowing incoming traffic to be routed directly to the server. DDNS allows users to connect to the VPN server using a domain name, instead of a static IP address.

However, using port forwarding and DDNS may not be an effective solution for remote VPN connections behind CGNAT. As CGNAT involves multiple devices sharing a single public IP address, it can be difficult to configure port forwarding to the correct device. Additionally, DDNS may not work correctly if the public IP address assigned to the router changes frequently. In these cases, it may be necessary to explore other solutions, such as using a VPN server with a public IP address or using a third-party VPN service.

It is important to note that remote VPN connections behind CGNAT can be complex and may require additional configuration and troubleshooting to ensure a stable and secure connection. It is recommended to consult with a network specialist or IT professional for assistance in setting up a remote VPN connection in these scenarios.

Following are some simpler options to Remote VPN home behind CGNAT

Solution - Router DDNS + OpenVPN

If you have an ASUS router, you can turn on DDNS IPV6 and Open VPN to establish a remote VPN connection behind CGNAT. To set this up, follow these steps:

1. Log in to your ASUS router's web interface.
2. Navigate to IPV6, and turn on IPV6 = Native if your ISP is PPPoE.
3. Navigate to the WAN section and enable the DDNS IPV6 option.
4. Navigate to VPN, configure the Open VPN settings, including the server address and port, as well as the client settings.
5. Save the settings and connect to the VPN server.

With these settings in place, you should be able to establish a remote VPN connection even if you're behind CGNAT. Keep in mind that this setup can be complex and may require additional configuration and troubleshooting to ensure a stable and secure connection. It is recommended to consult with a network specialist or IT professional for assistance in setting up a remote VPN connection in these scenarios.

Solution - Device level Tailscale

Tailscale is a VPN service that enables you to create a secure and private network between devices. It works by establishing peer-to-peer connections between devices, allowing them to communicate directly with one another without the need for a public IP address or port forwarding. Tailscale is an excellent option for remote VPN connections behind CGNAT, as it can work seamlessly in these scenarios.

To use Tailscale, follow these steps:

1. Sign up for a Tailscale account and download and install the Tailscale client on your device.
2. Connect your device to the internet and log in to your Tailscale account.
3. Once you've logged in, you should see a list of devices that are connected to your Tailscale network.
4. To add a new device to your Tailscale network, simply download and install the Tailscale client on the new device and log in using your Tailscale account credentials.
5. Once you've added the device to your Tailscale network, you should be able to communicate with it securely and privately, even if it's behind CGNAT.

Tailscale is an excellent solution for remote VPN connections behind CGNAT, as it can work seamlessly in these scenarios. Additionally, Tailscale is easy to set up and use and offers a range of features and tools to help you manage your network.

It is important to note that Tailscale cannot be installed directly on an ASUS router. The solution mentioned earlier involves installing the Tailscale client on each device that needs to connect to the network. This may not be ideal for some users, as it requires installing and configuring the client on each device separately. Additionally, Tailscale may not work with all devices and operating systems, so it is recommended to check the compatibility before installing.

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