AWS, Cloud Computing

5 Mins Read

Configure AWS VPN Connectivity to a Third-Party Network

1. Introduction
2. Configuring AWS
3. Configuring the Firewall
4. Checking the connection status
5. Summary
6. About CloudThat
8. Frequently Asked Questions


1. Introduction

A site-to-site VPN connection is usually done between two remote networks: a cloud provider and an on-premises network. It helps secure private communication between the remote resources or connects multiple resources in different office locations. IP sec connections work with the help of key exchange, authentication, and encryption providing enhanced security for data transfers.

This type of connection is permanent, which means it is generally a long-lived connection. However, other network connections like remote access VPN are temporarily used to connect to applications for a short time.

Some Benefits of IP-sec site to site VPNs are:

Today I will explain in detail the step-by-step procedure to connect an AWS site-to-site VPN connection to any third-party firewall or network environment. These will consist of basic steps to connect almost any local on-premises network to AWS. In today’s example, I would work with the SOPHOS-XG firewall.

Let us go to the required steps for connecting AWS VPN to a third-party network environment:

2. Configuring AWS

  1. Create A custom VPC in the AWS portal
  2. Create a customer gateway
    Provide a name for your customer gateway
    In our demo, we are taking routing as static
    Enter the Firewall’s public IP address of your on-premises in IP address
    We are not choosing any certificate and devices; you can choose if there is the requirement
  3. Create a Virtual private gateway and attach it with your VPC
    Choose a name for the virtual private gateway
    For ASN, choose Amazon default ASN
    Attach the VPG with your AWS VPC
  4. Create a Site-to-site VPN connection
    Enter the name for the connection
    Choose the virtual private gateway we created earlier
    Choose the customer gateway we created earlier
    Choose Routing as Static
    Define static IP as of on-premises subnet where your resources are
    Tunnel inside IP version: IPv4
    Local IPv4: Same as your on-premises subnet
    Remote IPv4: Your AWS subnet and create the VPN connection 
  5. Download the configuration file
    Choose vendor and platform as generic if your network is not mentioned in the option
    The configuration file is in text format, which you can use for the configuration at your on-premises firewall/environment.The text file contains information like:VPN connection ID, Virtual private-gateway ID, IKE version, Encryption algorithm type,DH group and pre-shared key for both IPsec tunnel 1 and 2 and much more

3. Configuring the Firewall

  1. To configure at your on-premises, here we have used SOPHOS-XG firewall as our local environment
    • Go to the admin page of your network environment
    • Navigate to Configure> VPN
    • Sophos -XG firewall uses an IPsec policy to create the VPN connection
    • Configure the details in Phase-1 which are needed such as:
    • Key-exchange
    • Key-life
    • DH-group
    • Encryption and Authentication method

    Here at Sophos-XG, you also need to configure a phase-2 with the same settings

    You can find other information needed in the configuration file which we downloaded in the previous step


  2. Add a VPN IP-sec tunnel in the network to connect to the AWS cloud environment
    • Give a descriptive name of your Choice
    • Connection type as a tunnel interface
    • Select the policy which we created in the previous step
    • Authentication type
    • Pre-shared key
    • Local ID: For Local ID, enter the public IP of the on-premises network
    • Remote ID: Enter the VPC CIDR block of AWS custom VPC we created

4. Checking the connection status

Everything is done and fulfilled according to the basic configuration needed for your VPN tunnel. The connection status will be UP and Running, which will also reflect in the AWS site to site VPN connections page.


5. Summary

We have successfully configured a site-to-site VPN connection between AWS and an on-premises network. Your remote network can be anything from a private network environment to a paid firewall environment. AWS provides a generic configuration file that contains detailed information about your AWS side VPN. You can choose between vendors like Cisco, Fortinet, Palo Alto, Juniper, etc.

You can start using your up and running tunnel to transfer data, data migration, network drives sharing, and more. VPNs make the transfer secure, highly available, and reliable.

6. About CloudThat

We here at CloudThat are the official AWS (Amazon Web Services) Advanced Consulting Partner and Training partner and Microsoft gold partner, helping people develop knowledge on cloud and help their businesses aim for higher goals using best in industry cloud computing practices and expertise. We are on a mission to build a robust cloud computing ecosystem by disseminating knowledge on technological intricacies within the cloud space. Our blogs, webinars, case studies, and white papers enable all the stakeholders in the cloud computing sphere.

Feel free to drop a comment or any queries that you have regarding AWS services, cloud adoption, consulting and we will get back to you quickly. To get started, go through our Expert Advisory page and Managed Services Package that is CloudThat’s offerings.

7. Frequently Asked Questions

AWS VPN establishes connectivity between various networks that includes on-premises networks, remote workplaces, client devices, and AWS global network. The AWS VPN consists of two main services: 1) AWS Client VPN and 2) AWS site-to-site VPN. AWS client VPN helps to manage remote access by connecting users with AWS or on-premises resources. AWS Site-to-Site VPN establishes encrypted tunnels between Amazon Virtual Private Clouds and end-user networks.

Yes, AWS VPN comes with additional encryption, integrity, and key exchange algorithms. The advanced algorithms ensure higher security and protect your data, assure higher performance for faster transfer rates, and help in meeting compliance requirements with ease.

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WRITTEN BY Akshay Mishra



  1. Hitesh Lodha

    Mar 16, 2022


    Very well explained 👍😇

    • Akshay Mishra

      Mar 24, 2022


      Thank you Hitesh

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