Site-to-Site VPN Integration for SAP HANA in AWS

Many enterprises, such as insurance companies, maintain on-premises databases (e.g., SAP HANA) due to customer preferences, regulatory requirements, or legacy system constraints. These businesses often need to integrate their existing infrastructure with AWS workloads.

A Site-to-Site VPN enables secure, private communication between AWS and on-premises networks over the internet.

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📌 Why Does This Use Case Require a Site-to-Site VPN?

✔ AWS Workloads Need to Connect to SAP HANA – Since SAP HANA remains on-premises, AWS resources (e.g., EC2, Lambda) must connect securely. ✔ Customer Requires a Private Connection – A VPN ensures encrypted traffic between AWS and SAP HANA. ✔ No Direct Internet Exposure – SAP HANA remains isolated while AWS applications access it through a VPN tunnel.

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📌 Key Components of an AWS Site-to-Site VPN

Component	Description
Customer Gateway (CGW)	Represents the on-premises VPN device that connects to AWS.
Virtual Private Gateway (VGW)	A managed AWS VPN endpoint that attaches to a VPC for connectivity.
Static/Internet-Routable IP Address	Required for the Customer Gateway (on-premises) to establish a VPN tunnel with AWS.
VPC Route Table Updates	Needed to ensure AWS resources can communicate with on-premises resources.
IKE/IPsec Tunnel	Used to establish a secure encrypted connection over the internet.

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📌 Why is Option C Correct?

✅ C. An Internet-routable IP address (static) of the customer gateway's external interface for the on-premises network

✔ The on-premises VPN device (Customer Gateway) must have a static public IP address that AWS can connect to. ✔ AWS does not support dynamic IPs for VPN endpoints, so a fixed, internet-routable address is required. ✔ This ensures a stable IKE (Internet Key Exchange) negotiation for establishing the IPSec VPN tunnel.

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📌 Why Are the Other Options Incorrect?

Option	Explanation
❌ A. An EIP to the Virtual Private Gateway	AWS Virtual Private Gateway (VGW) does not require an Elastic IP (EIP). AWS handles its routing automatically.
❌ B. The main route table in your VPC to route traffic through a NAT instance	NAT instances are used for outbound internet traffic from private subnets, not for VPN routing.
❌ D. A dedicated NAT instance in a public subnet	NAT instances are not required for VPN connectivity since the Virtual Private Gateway (VGW) handles routing securely.

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📌 Step-by-Step: Setting Up a Site-to-Site VPN for SAP HANA

✅ Step 1: Configure the Customer Gateway (On-Premises)

✔ Assign a static, internet-routable IP address to the VPN appliance (firewall/router) in the on-premises network. ✔ Ensure the VPN device supports IKEv1 or IKEv2 for AWS VPN connectivity. ✔ Configure the Customer Gateway settings (e.g., encryption algorithms, pre-shared key).

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✅ Step 2: Create a Virtual Private Gateway (VGW) in AWS

1️⃣ Open the AWS Management Console. 2️⃣ Navigate to VPC → Virtual Private Gateways. 3️⃣ Click Create Virtual Private Gateway. 4️⃣ Attach the VGW to your AWS VPC.

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✅ Step 3: Create a Site-to-Site VPN Connection

1️⃣ Navigate to VPC → Site-to-Site VPN Connections. 2️⃣ Click Create VPN Connection. 3️⃣ Choose the Virtual Private Gateway (VGW). 4️⃣ Select Customer Gateway and enter the static public IP address from Step 1. 5️⃣ Choose IKEv2 or IKEv1 as the VPN negotiation method. 6️⃣ Click Create VPN Connection.

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✅ Step 4: Update AWS VPC Route Tables

✔ Modify the route table to send SAP HANA traffic through the VPN tunnel. ✔ Example:

vbnetCopyEditDestination: 10.0.0.0/16 → Target: Virtual Private Gateway (VGW)

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📌 Secure VPN Traffic Flow

1️⃣ AWS VPC Resources (EC2, Lambda) → VPN Tunnel 2️⃣ VPN Tunnel → Customer Gateway (On-Premises) → SAP HANA 3️⃣ SAP HANA Sends Responses via VPN Tunnel to AWS

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📌 Best Practices for VPN Connectivity

✅ Use AWS Site-to-Site VPN for encrypted traffic between AWS and SAP HANA. ✅ Enable VPN redundancy by setting up two tunnels for high availability. ✅ Monitor VPN performance using Amazon CloudWatch. ✅ Optimize routing by using AWS Transit Gateway if multiple VPCs need access to SAP HANA.

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📌 Summary

🚀 To integrate SAP HANA with AWS workloads, SecureCart: ✔ Uses a Site-to-Site VPN for secure AWS connectivity. ✔ Configures a Customer Gateway with a static public IP. ✔ Establishes a Virtual Private Gateway (VGW) in AWS. ✔ Updates VPC route tables to direct traffic through the VPN.