AWS Site-to-Site VPN Tutorial: Architecture, Pricing, Use Cases, and Hands-On Guide for Networking and content delivery

1. Introduction

AWS Site-to-Site VPN is an AWS managed networking service that creates encrypted IPsec tunnels between your on-premises network (or another network) and your Amazon VPC or AWS Transit Gateway. It’s commonly used to extend private network connectivity into AWS without using the public internet in cleartext.

In simple terms: you configure a VPN device (your router/firewall, or a software VPN appliance) to connect to AWS, and AWS provisions two redundant VPN tunnels. Your workloads in AWS can then communicate with your on-premises workloads using private IP addresses over encrypted tunnels.

Technically, AWS Site-to-Site VPN terminates on either a virtual private gateway (VGW) attached to a single VPC or a transit gateway (TGW) for hub-and-spoke/multi-VPC connectivity. It supports dynamic routing using BGP or static routing, and uses standard IPsec/IKE to establish secure tunnels over the internet.

It solves the problem of securely connecting private networks across locations—hybrid cloud connectivity—without requiring dedicated circuits (like AWS Direct Connect), and without exposing internal traffic unencrypted.

2. What is AWS Site-to-Site VPN?

Official purpose: AWS Site-to-Site VPN provides secure, encrypted connectivity between your network and AWS over an IPsec VPN connection. It’s part of AWS’s hybrid connectivity portfolio under Networking and content delivery.

Core capabilities

Create IPsec tunnels between your customer gateway and AWS.
Use two tunnels per VPN connection for redundancy.
Support dynamic routing (BGP) or static routes (depending on your setup).
Terminate VPNs on:
Virtual Private Gateway (VGW) for a single VPC, or
Transit Gateway (TGW) for scalable hub-and-spoke architectures.
Optionally enable VPN acceleration (feature availability and mechanics can change; verify in official docs).

Major components (key terms you’ll see in AWS)

Customer gateway (CGW): The on-premises VPN endpoint definition in AWS (public IP address and routing type/ASN). This represents your device, even if that device is a software appliance.
Customer gateway device: The actual router/firewall/VPN appliance on your side.
VPN connection: The AWS resource that includes two IPsec tunnels and routing configuration.
Tunnel endpoints: AWS-provided public IP addresses for each tunnel.
Virtual private gateway (VGW): AWS-side VPN endpoint attached to a VPC.
Transit gateway (TGW): AWS hub for connecting multiple VPCs and on-premises networks (VPN and/or Direct Connect).
Route tables and route propagation: How traffic learns to use the VPN path.

Service type

Managed network connectivity service (control plane managed by AWS).
Data plane runs over the public internet but is encrypted with IPsec.

Scope (regional/account)

AWS Site-to-Site VPN is a Regional service in practice: you create VPN connections in a specific AWS Region and attach them to VGW/TGW resources in that Region.
Resources are scoped to your AWS account and Region (like VPCs and Transit Gateways).

How it fits into the AWS ecosystem

AWS Site-to-Site VPN commonly integrates with: – Amazon VPC (subnets, route tables, security groups, NACLs) – AWS Transit Gateway (centralized routing across many VPCs) – AWS Direct Connect (often paired as backup connectivity) – AWS Network Manager (visibility/monitoring of global networks; verify exact supported resource views in docs) – Amazon CloudWatch (metrics/alarms for tunnel state and throughput) – AWS CloudTrail (audit logging for API actions on VPN resources)

3. Why use AWS Site-to-Site VPN?

Business reasons

Faster hybrid adoption: Connect to AWS quickly without waiting for dedicated circuits.
Lower upfront cost: No physical circuit or colocation requirement.
Incremental migration: Extend on-prem networks to AWS during phased migration.

Technical reasons

Encrypted in transit: IPsec encryption protects traffic over the internet.
Private addressing end-to-end: Applications can communicate using RFC1918 IPs (your internal IP ranges).
Redundant tunnels: Each VPN connection includes two tunnels to support high availability designs.
Routing flexibility: Use BGP for dynamic routing or static routes for simpler environments.

Operational reasons

Managed AWS endpoint: AWS manages the VPN endpoint on its side (VGW/TGW).
Standard protocols: Works with many existing network devices and SD-WAN platforms.
Automation-friendly: Build and manage using AWS Console, AWS CLI, IaC (CloudFormation/Terraform).

Security/compliance reasons

Traffic encryption: Helps meet security requirements for data in transit.
Auditable changes: Resource changes are logged via CloudTrail.
Segmentation: Use VPC route tables, TGW route tables, and security groups to enforce network boundaries.

Scalability/performance reasons

TGW integration: Scale to many VPCs and many remote sites with centralized routing.
Active/active possibilities: With BGP and appropriate settings, you can use multiple tunnels and Equal-Cost Multi-Path (ECMP) in some designs (verify current constraints by gateway type in official docs).

When teams should choose AWS Site-to-Site VPN

You need quick, encrypted hybrid connectivity.
You need backup connectivity for Direct Connect.
You have moderate bandwidth requirements and can tolerate internet variability.
You need to connect a branch office, datacenter, or partner network.

When teams should not choose it

You require consistent low-latency and high-throughput connectivity with strict SLAs: consider AWS Direct Connect.
You need user-to-VPC remote access for individuals: consider AWS Client VPN instead.
You need VPC-to-VPC connectivity only within AWS: consider VPC Peering or Transit Gateway (without VPN).
Your environment requires complex L7 security inspection inline: you may need additional network security appliances and architecture work.

4. Where is AWS Site-to-Site VPN used?

Industries

Finance and insurance (encrypted hybrid connectivity, regulated environments)
Healthcare (secure connectivity for clinical systems; compliance-driven)
Retail (store/branch connectivity)
Manufacturing (plant/OT integration with cloud analytics)
SaaS/tech (hybrid builds, migrations, DR connectivity)

Team types

Network engineering teams (routing, IPsec, BGP)
Cloud platform teams (landing zones, shared connectivity)
Security engineering teams (segmentation, encryption requirements)
DevOps/SRE (hybrid monitoring, reliability, incident response)

Workloads

Hybrid web applications (app tier in AWS, database on-prem temporarily)
Data transfer pipelines (on-prem data to AWS analytics)
Identity and directory integration (AD/LDAP connectivity)
Backup and disaster recovery (replication from on-prem to AWS)

Architectures

Single VPC hybrid extension using VGW
Multi-VPC hub-and-spoke using Transit Gateway
Dual connectivity: Direct Connect + VPN backup
Multi-site connectivity: many branches into a TGW

Production vs dev/test usage

Dev/test: quick connectivity to test hybrid patterns without long procurement.
Production: commonly used as:
primary connectivity for smaller sites, or
secondary/backup path for critical sites with Direct Connect.

5. Top Use Cases and Scenarios

Below are realistic scenarios where AWS Site-to-Site VPN is commonly used.

1) Hybrid application migration (lift-and-shift)

Problem: You need AWS compute to access on-prem databases while migrating.
Why this service fits: Encrypted connectivity with private routing; quick to set up.
Example scenario: Move application servers to EC2, keep Oracle on-prem until cutover.

2) Direct Connect backup (resiliency)

Problem: Dedicated circuits can fail; you need failover connectivity.
Why this service fits: VPN can act as a secondary path when Direct Connect is down.
Example scenario: Dual-homed site uses Direct Connect for normal operations and AWS Site-to-Site VPN for failover.

3) Branch office to AWS (no datacenter)

Problem: Small branch needs access to workloads in AWS without MPLS.
Why this service fits: Uses internet + IPsec; compatible with many branch routers/SD-WAN.
Example scenario: Retail stores connect to a TGW in the nearest Region.

4) Disaster recovery networking

Problem: You need private network reachability for DR tests and failover.
Why this service fits: Create VPN to DR VPC; keep it warm for replication and drills.
Example scenario: On-prem VMware replication targets EC2/EBS-backed appliances in AWS.

5) Secure ingestion to AWS analytics

Problem: Send logs/metrics/data from on-prem securely to AWS.
Why this service fits: Encrypted tunnels; controlled routing; avoids exposing ingestion endpoints publicly.
Example scenario: Industrial telemetry flows to Amazon Kinesis endpoints via private routing and NAT/egress patterns.

6) Partner network connectivity

Problem: Connect a partner environment to a shared services VPC.
Why this service fits: Standard IPsec; route-level control; separate VPNs per partner.
Example scenario: B2B integration where partner sends data to internal APIs in AWS.

7) Centralized inspection VPC (with TGW)

Problem: Multiple VPCs need consistent egress and inspection policies.
Why this service fits: VPN into TGW enables centralized routing; combine with inspection VPC architecture.
Example scenario: Remote datacenters connect via VPN to TGW; traffic routed through a firewall VPC.

8) Temporary connectivity during datacenter move

Problem: You need a bridge while moving infrastructure and changing IP ranges.
Why this service fits: Quick to spin up and tear down; static routes possible.
Example scenario: Month-long transition connectivity for cutover weekends.

9) Hybrid identity services (AD/LDAP, RADIUS)

Problem: AWS workloads need to authenticate against on-prem identity.
Why this service fits: Private IP connectivity reduces exposure; stable routing.
Example scenario: EC2 domain-joined servers use on-prem domain controllers during migration.

10) Multi-site connectivity consolidation

Problem: Many sites connect to multiple VPCs; routing becomes hard.
Why this service fits: Use TGW to simplify into hub-and-spoke; manage routes centrally.
Example scenario: 20 branches connect to a TGW; shared services VPC provides DNS, logging, patching.

11) Secure admin plane access (private tooling)

Problem: Admin tools must reach instances without exposing SSH/RDP to internet.
Why this service fits: VPN provides a private path from corporate network to private subnets.
Example scenario: Bastion hosts removed; admins connect through corporate VPN device to AWS private IPs.

12) Lab environments and training

Problem: Need to teach IPsec/BGP hybrid networking with minimal hardware.
Why this service fits: Can be simulated using a software VPN appliance on EC2 as a customer gateway.
Example scenario: Training lab uses strongSwan on Linux to establish tunnels to a VPC.

6. Core Features

Managed IPsec VPN (two redundant tunnels)

What it does: Provisions an IPsec VPN connection with two tunnels to AWS-managed endpoints.
Why it matters: Redundancy is built in; you can design for failover.
Practical benefit: Higher availability than a single tunnel.
Caveats: You still must configure your customer gateway to use both tunnels; active/active vs active/standby depends on routing mode and device capability.

Termination on Virtual Private Gateway (VGW) or Transit Gateway (TGW)

What it does: Lets you terminate VPN on a VPC (VGW) or a centralized router (TGW).
Why it matters: Determines scalability and route management model.
Practical benefit: TGW supports multi-VPC connectivity patterns.
Caveats: TGW introduces its own routing concepts (TGW route tables, attachments) and costs.

Dynamic routing with BGP

What it does: Exchanges routes using BGP between your customer gateway and AWS.
Why it matters: Enables route failover and simplifies operations as networks change.
Practical benefit: Automatic routing updates; supports more resilient designs.
Caveats: Requires BGP-capable device and correct ASN/peering setup.

Static routing (no BGP)

What it does: You manually define remote network prefixes reachable via the VPN.
Why it matters: Simple for small networks or where BGP isn’t available.
Practical benefit: Lower complexity.
Caveats: Manual updates required; failover behavior is more limited than well-designed BGP.

Tunnel options (IKE/IPsec parameters)

What it does: AWS provides tunnel configuration details (public endpoint IPs, pre-shared keys, encryption/authentication settings, inside tunnel addresses for route-based designs).
Why it matters: Interoperability depends on matching parameters between AWS and your device.
Practical benefit: AWS generates vendor-specific configuration templates for many devices.
Caveats: Your security policy may require specific ciphers; verify what your device supports and what AWS currently offers (cipher suites evolve—verify in official docs).

VPN acceleration (optional)

What it does: Provides an option intended to improve performance by leveraging AWS global edge networking for VPN traffic.
Why it matters: Can reduce latency variation for some geographies.
Practical benefit: Better user experience and potentially higher throughput consistency.
Caveats: Additional costs and constraints may apply; availability and implementation details can change—verify in official docs.

Integration with VPC routing (route tables, propagation)

What it does: Lets your VPC route tables direct traffic for on-prem prefixes toward the VGW/TGW.
Why it matters: Routing determines what traffic uses the VPN.
Practical benefit: Fine-grained control by subnet and route table.
Caveats: Misconfigured routes are the #1 cause of “VPN is up but traffic doesn’t flow.”

Monitoring via CloudWatch (tunnel telemetry/metrics)

What it does: Publishes metrics such as tunnel state and data transfer (exact metric names and availability can vary by gateway type—verify in docs).
Why it matters: Enables alerting and operational visibility.
Practical benefit: Trigger alarms when a tunnel goes down or throughput drops.
Caveats: CloudWatch metrics won’t replace device-side IPsec logs; keep logs on your customer gateway device for deep troubleshooting.

Auditing via CloudTrail

What it does: Records API calls for creating/modifying/deleting VPN resources.
Why it matters: Governance and security auditing.
Practical benefit: Trace changes during incidents and reviews.
Caveats: CloudTrail logs control plane actions, not packet-level events.

7. Architecture and How It Works

High-level service architecture

AWS Site-to-Site VPN is built around an AWS-managed termination point (VGW or TGW) and your customer gateway device. The control plane creates and manages VPN resources; the data plane uses IPsec tunnels over the internet.

Data flow (typical)

A workload in a VPC sends traffic to an on-premises prefix.
The VPC route table matches that prefix and forwards traffic to the VGW (or to TGW, then to VPN attachment).
AWS encrypts traffic into IPsec and sends it to your customer gateway’s public IP over the internet.
Your customer gateway decrypts and routes it internally.

Control flow (typical)

You define:
Customer gateway (public IP, ASN if BGP)
Gateway (VGW/TGW)
VPN connection (routing mode, tunnel options)
AWS generates tunnel configuration details.
You apply compatible configuration to your device.
Tunnels establish using IKE and IPsec negotiation.

Integrations with related services

Amazon VPC: subnets, route tables, NACLs, security groups.
AWS Transit Gateway: route tables, VPN attachments, multi-VPC routing.
AWS Direct Connect: use VPN as backup; may also run VPN over DX in some designs (verify best practices for your environment).
AWS Network Manager: visualize and monitor network topology (verify exact supported views and metrics in docs).
CloudWatch + CloudTrail: monitoring and auditing.

Dependency services

VPCs, route tables, and gateway resources are mandatory dependencies.
Customer gateway device must be reachable on the internet (public IP) and allow UDP 500/4500 and ESP as required.

Security/authentication model

Uses pre-shared keys (PSK) or device-supported methods as provided by AWS configuration templates.
Negotiation is via IKE; data encryption via IPsec ESP.
Access to create/modify VPN resources is governed by IAM permissions.

Networking model

Routing is based on:
VPC route tables (and optionally TGW route tables)
VPN static routes or BGP-learned routes
Security enforcement occurs at:
Security groups (stateful)
Network ACLs (stateless)
On-prem firewalls
Optional inspection VPC appliances

Monitoring/logging/governance considerations

Use CloudWatch alarms for tunnel down conditions.
Use CloudTrail for change history (who changed what).
Rely on customer gateway device logs for detailed IKE/IPsec negotiation issues.

Simple architecture diagram

flowchart LR
  OnPrem[On-prem network\n(Customer Gateway Device)] -- "IPsec (2 tunnels)\nOver Internet" --> AWSGW[VGW or TGW]
  AWSGW --> VPC[VPC Subnets\n(Private workloads)]

Production-style architecture diagram (hybrid, multi-VPC, centralized routing)

flowchart TB
  subgraph Branches["On-prem / Branch Sites"]
    B1[Site A\nRouter/Firewall]
    B2[Site B\nRouter/Firewall]
  end

  Internet[(Internet)]

  subgraph AWSRegion["AWS Region"]
    TGW[AWS Transit Gateway]
    RT[TGW Route Tables]
    VPC1[Shared Services VPC\nDNS / Logging]
    VPC2[App VPC]
    VPC3[Inspection VPC\nFirewall Appliances]
    CW[CloudWatch Alarms]
    CT[CloudTrail]
  end

  B1 -- "IPsec VPN (2 tunnels)" --> Internet --> TGW
  B2 -- "IPsec VPN (2 tunnels)" --> Internet --> TGW

  TGW <--> RT
  TGW --> VPC3 --> VPC1
  TGW --> VPC3 --> VPC2

  TGW -.metrics.-> CW
  TGW -.API audit.-> CT

8. Prerequisites

AWS account requirements

An AWS account with access to Amazon VPC and AWS Site-to-Site VPN.
A billing method configured (VPN has hourly charges; data transfer charges may apply).

Permissions / IAM

Minimum permissions (conceptual; scope as needed): – ec2:CreateVpnConnection, ec2:DeleteVpnConnection – ec2:CreateCustomerGateway, ec2:DeleteCustomerGateway – ec2:CreateVpnGateway, ec2:AttachVpnGateway, ec2:DetachVpnGateway, ec2:DeleteVpnGateway – ec2:CreateRoute, ec2:ReplaceRoute, ec2:EnableVgwRoutePropagation – ec2:Describe*

For production, use least privilege with scoped resource ARNs and conditions where possible.

Tools

AWS Console (sufficient for this lab)
Optional: AWS CLI v2 for verification/automation
https://docs.aws.amazon.com/cli/latest/userguide/getting-started-install.html

Region availability

AWS Site-to-Site VPN is available in many Regions, but confirm your target Region supports all needed features (especially acceleration) in official docs.

Quotas/limits

VPN-related quotas exist (e.g., number of VPN connections per gateway). Quotas can change. Check: https://docs.aws.amazon.com/vpc/latest/userguide/amazon-vpc-limits.html
and Service Quotas console.

Prerequisite services/resources

A VPC with subnets and route tables.
An internet-reachable public IP on your customer gateway device (for this lab, we’ll use an Elastic IP on an EC2 instance).
Non-overlapping CIDR blocks between on-prem and VPC networks.

9. Pricing / Cost

AWS Site-to-Site VPN pricing is usage-based. Exact prices vary by Region and can change, so use official sources for current rates.

Official pricing references

AWS Site-to-Site VPN Pricing: https://aws.amazon.com/vpn/pricing/
AWS Pricing Calculator: https://calculator.aws/

Pricing dimensions (typical)

Common cost components include: – Hourly charge per VPN connection (a VPN connection includes two tunnels). – Data transfer charges: – Data transfer out from AWS to the internet is typically charged. – Data transfer within AWS or in-to-AWS may have different pricing rules. Always validate with AWS Data Transfer pricing: https://aws.amazon.com/ec2/pricing/on-demand/#Data_Transfer – Optional acceleration feature charges (if enabled): may add hourly and/or data processing charges (verify current model on pricing page).

Free tier

AWS Site-to-Site VPN is generally not free-tier eligible in the way some always-free services are. Verify current free tier conditions (if any) on the pricing page.

Primary cost drivers

Number of VPN connections (each includes two tunnels).
Hours running (24/7 vs part-time dev).
Data volume and direction (especially egress from AWS).
Use of Transit Gateway (TGW has its own hourly and data processing charges).
Additional infrastructure you run for the customer gateway (in this lab: EC2 instances, EIPs).

Hidden/indirect costs to watch

Elastic IP charges (especially if allocated and unused).
NAT Gateway charges if you introduce NAT for private subnet egress.
Transit Gateway costs if you choose TGW instead of VGW.
Operational cost: managing device configuration, key rotation, monitoring, incident response.

Cost optimization tips

Prefer one VPN connection per site with proper routing instead of many ad-hoc VPNs.
Use Transit Gateway thoughtfully—great for scale, but it adds cost. For single-VPC/simple needs, VGW may be cheaper.
Set up CloudWatch alarms to detect tunnel down early and reduce troubleshooting time.
For dev/test, schedule teardown when not needed (but note that repeated changes can increase operational overhead).

Example low-cost starter estimate (how to think about it)

A minimal lab often includes: – 1 VPN connection (hourly) – 1–2 EC2 instances (customer gateway + test host) – 1 Elastic IP – Small data transfer for testing

Because hourly prices vary by Region and can change, calculate by entering: – VPN connection hours (e.g., 10 hours) – EC2 instance hours (e.g., 10 hours each) – Estimated GB transferred out of AWS

Use the AWS Pricing Calculator to get an accurate, Region-specific estimate.

Example production cost considerations

For production, consider: – Multiple sites (each with a VPN connection) – 24/7 operation – Higher data volumes (egress charges can dominate) – Transit Gateway hourly + processing charges (if used) – Direct Connect (if used) plus VPN backup

10. Step-by-Step Hands-On Tutorial

This lab creates a real AWS Site-to-Site VPN between: – A VPC that represents “AWS workloads” (with a VGW), and – A second VPC that represents an “on-premises network” (with an EC2-based customer gateway running strongSwan).

This is a common training pattern because it’s fully self-contained in AWS, but exercises real IPsec tunnel establishment.

Objective

Establish an AWS Site-to-Site VPN connection (two tunnels) between a VPC and a simulated on-prem network, then verify private IP connectivity between hosts over the VPN.

Lab Overview

You will build: – AWS VPC (aws-vpc): 10.0.0.0/16 – Private subnet with a test EC2 instance – Virtual Private Gateway (VGW) attached – On-prem VPC (onprem-vpc): 10.1.0.0/16 – Public subnet with a strongSwan VPN router EC2 instance + Elastic IP – Private subnet with a test EC2 instance (no public IP) – AWS Site-to-Site VPN – Customer Gateway (CGW) points to the strongSwan router Elastic IP – VPN connection uses static routing (simpler for labs)

Expected outcome: – VPN tunnels show UP (after configuration). – You can ping from the AWS private instance to the on-prem private instance using private IPs.

Notes before you start: – This lab incurs cost (VPN hourly, EC2, EIP, and possible data transfer). – IPsec configuration is sensitive. Follow the steps carefully and use the downloaded AWS configuration to avoid mismatched parameters. – Vendor-specific parameters evolve. If something doesn’t match your downloaded configuration, prefer the downloaded values.

Step 1: Create the two VPCs and subnets

Create two VPCs with non-overlapping CIDRs.

1) Create aws-vpc – CIDR: 10.0.0.0/16 – Subnets: – aws-private-subnet (e.g., 10.0.1.0/24) in one AZ

2) Create onprem-vpc – CIDR: 10.1.0.0/16 – Subnets: – onprem-public-subnet (e.g., 10.1.1.0/24) – onprem-private-subnet (e.g., 10.1.2.0/24)

3) Create and attach an Internet Gateway (IGW) to onprem-vpc.

4) Create route tables: – onprem-public-rt: default route 0.0.0.0/0 -> IGW – onprem-private-rt: no default internet route (yet)

Associate: – onprem-public-subnet -> onprem-public-rt – onprem-private-subnet -> onprem-private-rt

Expected outcome: You have two VPCs. The on-prem public subnet has internet access via IGW.

Step 2: Launch EC2 instances (strongSwan router + test hosts)

You will deploy three instances: 1) cgw-router (strongSwan) in onprem-public-subnet with Elastic IP
2) onprem-host in onprem-private-subnet with no public IP
3) aws-host in aws-private-subnet (you can give it a temporary public IP for setup, or use SSM; for simplicity, a public IP is okay for a lab but lock down SSH)

2A) Security groups

Create security groups:

SG: cgw-router-sg (attached to cgw-router) – Inbound: – UDP 500 from 0.0.0.0/0 (IKE) – UDP 4500 from 0.0.0.0/0 (NAT-T) – ESP (IP protocol 50) from 0.0.0.0/0 (if your environment requires it; some NAT paths rely on UDP encapsulation) – SSH (TCP 22) from your IP only – Outbound: allow all (for simplicity)

SG: onprem-host-sg – Inbound: – ICMP from 10.0.0.0/16 – SSH from 10.1.0.0/16 (or from cgw-router SG) – Outbound: allow all

SG: aws-host-sg – Inbound: – ICMP from 10.1.0.0/16 – SSH from your IP only (or from a bastion/SSM) – Outbound: allow all

2B) Launch instances

Launch cgw-router:
Subnet: onprem-public-subnet
Auto-assign public IPv4: Disable (we’ll attach an Elastic IP instead for stability)
Security group: cgw-router-sg
OS: Ubuntu LTS (commonly used in VPN appliance labs)
Allocate and associate an Elastic IP to cgw-router.
Launch onprem-host:
Subnet: onprem-private-subnet
Auto-assign public IPv4: disabled
Security group: onprem-host-sg
Launch aws-host:
Subnet: aws-private-subnet
Security group: aws-host-sg
For easy access, you may temporarily place it in a public subnet or assign a public IP; for best practice, use AWS Systems Manager Session Manager (requires additional setup). Keep the lab focused; choose what you can operate safely.

2C) Disable source/destination check on `cgw-router`

Because cgw-router will route traffic between subnets and the VPN, disable source/dest check: – EC2 Console → Instances → cgw-router → Networking → Change source/destination check → Disable

Expected outcome: Instances are running; the router has a stable Elastic IP; router is allowed to forward traffic.

Step 3: Configure on-prem VPC routing to use the router

You need the on-prem private subnet to route AWS VPC traffic to the VPN router instance.

1) In onprem-private-rt, add route: – Destination: 10.0.0.0/16 (AWS VPC CIDR) – Target: cgw-router instance (instance target in route table)

Expected outcome: Traffic from onprem-host to 10.0.0.0/16 will be sent to cgw-router.

Step 4: Create a Virtual Private Gateway (VGW) and attach it to aws-vpc

1) VPC Console → Virtual private gateways → Create VGW: – Name: aws-vgw – ASN: leave default unless you need a specific value (BGP-related; static routing doesn’t require it)

2) Attach VGW to aws-vpc.

Expected outcome: VGW exists and is attached to your VPC.

Step 5: Create the Customer Gateway (CGW)

1) VPC Console → Customer Gateways → Create customer gateway: – Name: onprem-cgw – Routing: Static (for this lab) – IP address: Elastic IP of cgw-router

Expected outcome: Customer gateway resource represents your strongSwan router.

Step 6: Create the VPN connection (static routes)

1) VPC Console → Site-to-Site VPN connections → Create VPN connection – Name: lab-s2s-vpn – Target gateway type: Virtual private gateway – Virtual private gateway: aws-vgw – Customer gateway: existing onprem-cgw – Routing options: Static – Static IP prefixes: add 10.1.0.0/16 (on-prem CIDR)

2) After creation, select the VPN connection and Download configuration. – Vendor: if “strongSwan” is available, choose it; otherwise select a “Generic” option and adapt. – Keep this file secure; it contains tunnel details and pre-shared keys.

Expected outcome: VPN connection exists with two tunnels in “DOWN” state until strongSwan is configured.

Step 7: Update aws-vpc route table to send on-prem traffic to VGW

In the route table associated with aws-private-subnet, add: – Destination: 10.1.0.0/16 – Target: aws-vgw

If your route table supports route propagation, you can also enable propagation from the VGW; for a lab, a manual route is explicit and easier to reason about.

Expected outcome: AWS instances know to route on-prem traffic to the VGW.

Step 8: Configure strongSwan on the customer gateway router

SSH to cgw-router using its Elastic IP.

8A) Install strongSwan and enable forwarding

Ubuntu example:

sudo apt-get update
sudo apt-get install -y strongswan strongswan-pki

# Enable IPv4 forwarding
echo "net.ipv4.ip_forward=1" | sudo tee /etc/sysctl.d/99-ipsec.conf
sudo sysctl -p /etc/sysctl.d/99-ipsec.conf

Allow forwarding in the instance firewall if you use UFW; if not using UFW, skip:

# If UFW is enabled:
sudo ufw allow 500/udp
sudo ufw allow 4500/udp
sudo ufw allow OpenSSH
sudo ufw disable  # For labs, you can disable to reduce variables; for production, configure it properly.

8B) Apply AWS tunnel configuration

Use the downloaded VPN configuration from AWS as the source of truth.

You must locate (per tunnel): – AWS tunnel endpoint public IP (two values) – Pre-shared keys (two values) – IKE version and encryption/authentication algorithms – Any required lifetimes/DPD settings – (If using route-based VTI) inside tunnel IP addressing and marks

Because these values are generated per VPN, do not blindly copy parameters from a blog post. Use your downloaded configuration.

A common strongSwan layout is: – /etc/ipsec.conf – /etc/ipsec.secrets

Below is a template that you should adapt to match your downloaded config. If your AWS download provides a strongSwan-ready config, use it directly.

/etc/ipsec.conf (template – adjust to your downloaded config)

config setup
  charondebug="ike 1, knl 1, cfg 0"

conn %default
  keyexchange=ikev2
  type=tunnel
  authby=psk
  dpdaction=restart
  dpddelay=10s
  dpdtimeout=30s
  rekey=yes
  keyingtries=%forever

  # Local (customer gateway)
  left=%defaultroute
  leftid=<CGW_PUBLIC_IP>

  # For route-based/VTI setups, many templates use 0.0.0.0/0 selectors
  leftsubnet=0.0.0.0/0
  rightsubnet=0.0.0.0/0

conn tunnel1
  right=<AWS_TUNNEL1_PUBLIC_IP>
  auto=start
  ike=<MATCH_DOWNLOADED_IKE_PARAMS>
  esp=<MATCH_DOWNLOADED_ESP_PARAMS>

conn tunnel2
  right=<AWS_TUNNEL2_PUBLIC_IP>
  auto=start
  ike=<MATCH_DOWNLOADED_IKE_PARAMS>
  esp=<MATCH_DOWNLOADED_ESP_PARAMS>

/etc/ipsec.secrets (template)

<CGW_PUBLIC_IP> <AWS_TUNNEL1_PUBLIC_IP> : PSK "<TUNNEL1_PSK>"
<CGW_PUBLIC_IP> <AWS_TUNNEL2_PUBLIC_IP> : PSK "<TUNNEL2_PSK>"

If your downloaded config specifies IKEv1, set keyexchange=ikev1. If it specifies particular proposals (AES/SHA/DH groups), match them exactly.

8C) (Optional but common) Route-based VTI interface setup

Many modern AWS Site-to-Site VPN device configs use route-based VPN with VTIs. AWS often provides a sample up/down script for Linux-based devices.

If your downloaded strongSwan config includes VTI instructions, follow it. If it does not, consult AWS documentation for Linux customer gateway examples and ensure you understand how marks, VTIs, and routes are applied.

A common pattern is: – Create vti0 for tunnel1 and vti1 for tunnel2 – Assign inside tunnel IPs (169.254.x.x/30 pairs) – Add routes to AWS CIDR via the VTI – Disable policy enforcement on the VTI interface (disable_policy=1) so the kernel routes correctly

Because inside IPs and marks are generated per tunnel, use your downloaded config.

8D) Restart strongSwan

sudo systemctl restart strongswan
sudo systemctl status strongswan --no-pager

Check status:

sudo ipsec statusall

Expected outcome: strongSwan attempts to bring up both tunnels. Within a few minutes, the AWS console should show tunnels as UP if parameters match and security groups/routes allow negotiation.

Step 9: Verify tunnel status in AWS

In the AWS Console: – VPC → Site-to-Site VPN connections → lab-s2s-vpn – Check both tunnels

Expected outcome: At least one tunnel shows UP. Ideally both show UP.

Step 10: Test private connectivity end-to-end

You want to test: – aws-host (10.0.x.x) → onprem-host (10.1.x.x) – Optionally, the reverse direction as well

From aws-host:

ping -c 4 <ONPREM_HOST_PRIVATE_IP>

From onprem-host:

ping -c 4 <AWS_HOST_PRIVATE_IP>

Expected outcome: Pings succeed. If not, see Troubleshooting.

Validation

Use this checklist:

1) Tunnels are UP – AWS Console shows tunnel(s) UP. – On cgw-router, sudo ipsec statusall shows established SAs.

2) Routes are correct – aws-private-subnet route table has 10.1.0.0/16 -> VGW – VPN connection has static route 10.1.0.0/16 – onprem-private-rt routes 10.0.0.0/16 -> cgw-router

3) Security groups/NACLs allow traffic – ICMP allowed between CIDRs (for ping) – UDP 500/4500 allowed to cgw-router

4) Forwarding is enabled – net.ipv4.ip_forward=1 on cgw-router – Source/dest check disabled on cgw-router

Troubleshooting

Common issues and realistic fixes:

Issue: Tunnels stay DOWN – Verify cgw-router-sg allows UDP 500 and 4500 inbound. – Verify you used the correct Elastic IP as the Customer Gateway IP. – Confirm your leftid/right/PSKs match the downloaded config exactly. – Check strongSwan logs: bash sudo journalctl -u strongswan --no-pager | tail -200 – Confirm time sync (clock skew can break IKE). Ensure NTP is working.

Issue: Tunnel is UP but ping fails – Route tables missing: – AWS route table missing 10.1.0.0/16 -> VGW – onprem-private-rt missing 10.0.0.0/16 -> cgw-router – Linux forwarding not enabled on cgw-router. – Source/dest check not disabled on cgw-router. – Security group doesn’t allow ICMP (or test TCP 22/80 instead). – NACLs blocking traffic (less common in labs, but possible).

Issue: Only one tunnel is UP – This can be normal if your device is only configured for one tunnel or routing prefers one. – Ensure both tunnels are configured and allowed through security group. – For active/active, typically you need BGP and device support (verify for your design).

Issue: StrongSwan proposals don’t match – AWS config specifies exact IKE/ESP proposals; strongSwan must match. – Don’t reuse generic AES/SHA/DH settings—copy from the downloaded config.

Cleanup

To avoid ongoing charges, delete resources in roughly this order:

1) Delete VPN connection lab-s2s-vpn 2) Delete Customer Gateway onprem-cgw 3) Detach and delete Virtual Private Gateway aws-vgw 4) Terminate EC2 instances: cgw-router, onprem-host, aws-host 5) Release Elastic IP (after instance termination) 6) Delete route table entries you created 7) Delete subnets and VPCs (aws-vpc, onprem-vpc) 8) Delete security groups created for the lab

11. Best Practices

Architecture best practices

Prefer Transit Gateway for multi-VPC, multi-site architectures to simplify routing and segmentation.
Design for failure domains:
Use both tunnels.
Consider separate customer gateway devices (or separate ISPs) for higher resilience.
Avoid overlapping CIDRs; plan IP addressing early.

IAM/security best practices

Restrict who can create/modify VPN resources with least-privilege IAM.
Require MFA and use roles with session-based access for admins.
Use CloudTrail and centralized logging accounts to audit changes.

Cost best practices

Right-size connectivity:
Single-VPC needs may not require TGW.
Avoid leaving dev VPNs running 24/7.
Monitor data transfer out; design data flows to minimize egress.

Performance best practices

Use BGP for better failover and potential multi-tunnel utilization (device-dependent).
Place VPN endpoints in the Region closest to your on-prem site to reduce latency.
If considering acceleration, test and validate improvements versus added cost (verify current behavior in docs).

Reliability best practices

Use redundant customer gateways (separate devices/links) for critical systems.
Implement CloudWatch alarms on tunnel status.
Document runbooks for tunnel failure, rekey events, and routing changes.

Operations best practices

Keep device configuration under version control (securely), with change review.
Standardize naming/tagging: environment, site, owner, cost center.
Rotate keys and review cipher policies periodically (based on security requirements).

Governance/tagging/naming best practices

Tag VPN resources: Environment, Owner, Application, CostCenter, Site.
Use consistent names: vpn-prod-siteA, cgw-siteA-fw1, tgw-prod-core.

12. Security Considerations

Identity and access model

AWS resource access is governed by IAM:
Use role-based access and least privilege.
Restrict actions like CreateVpnConnection and ModifyVpnConnectionOptions.

Encryption

Data is encrypted in transit using IPsec.
Your actual encryption strength depends on negotiated ciphers and DH groups.
Align VPN cryptography with your organization’s security baseline; confirm AWS-supported proposals in current documentation.

Network exposure

The customer gateway device must be reachable on the public internet (public IP).
Ensure perimeter controls allow only necessary protocols:
UDP 500 (IKE)
UDP 4500 (NAT-T)
ESP (protocol 50) if required by your setup

Secrets handling (PSKs)

Pre-shared keys are sensitive secrets.
Store PSKs securely (secret managers, encrypted vaults); do not paste into tickets or chat.
Rotate PSKs according to your policy; ensure change windows and rollback plans.

Audit/logging

CloudTrail: audit VPN resource changes.
Device logs: maintain IKE/IPsec logs on customer gateway for forensics.
CloudWatch: alarm on tunnel down and anomalous throughput.

Compliance considerations

Many compliance frameworks require encryption in transit; IPsec supports that requirement.
Compliance also requires access control and audit trails—use IAM + CloudTrail.
Verify whether your compliance needs require dedicated connectivity (Direct Connect) or specific cryptographic modules (this is environment-specific).

Common security mistakes

Allowing UDP 500/4500 from everywhere without additional controls in production.
Reusing PSKs across environments.
Not segmenting routes (advertising overly broad prefixes).
Missing monitoring—tunnel down goes unnoticed.

Secure deployment recommendations

Use restricted firewall rules (limit IKE/NAT-T sources when possible).
Prefer BGP with proper filtering to control route propagation.
Use separate VPNs for separate trust zones (prod vs dev) and segment with TGW route tables.

13. Limitations and Gotchas

Limits and exact numbers change. Always confirm in official docs and Service Quotas.

Known limitations / constraints (common)

Internet-based VPN performance is variable (latency/jitter/packet loss depend on internet path).
Some advanced routing behaviors require BGP and compatible devices.
Troubleshooting often requires coordinating logs/telemetry from both AWS and the customer gateway device.

Quotas

Limits on:
VPN connections per VGW/TGW
Routes per VPN (static) and route table capacities
Check Service Quotas and VPC limits documentation.

Regional constraints

VPN resources are created per Region; cross-Region connectivity requires separate design (e.g., TGW peering, Cloud WAN, or separate VPNs).

Pricing surprises

Data transfer out of AWS can be a major cost driver.
Transit Gateway adds hourly and per-GB processing costs.
Acceleration (if enabled) may add additional hourly/data charges.

Compatibility issues

Not all devices support the same IKE/IPsec proposals.
NAT in front of the customer gateway can complicate negotiation (NAT-T).
MTU/MSS issues can cause “it connects but apps are slow.” TCP MSS clamping is often required on some devices—verify with your vendor and AWS guidance.

Operational gotchas

“Tunnel UP but no traffic” is almost always routing/security group/NACL/source-dest-check related.
Overlapping CIDRs prevent routing and may require NAT or readdressing (complex).
Rekey events can briefly disrupt traffic if device behavior differs.

Migration challenges

Moving from VGW to TGW-based VPN changes routing model and may require downtime/careful cutover.
Adding sites later may require redesign if you started with point-to-point VGW patterns.

Vendor-specific nuances

Some vendors require policy-based selectors; AWS commonly uses route-based constructs. Use AWS-provided vendor templates whenever possible.
SD-WAN platforms may abstract IPsec details; ensure they still match AWS parameters.

14. Comparison with Alternatives

AWS Site-to-Site VPN is one option among several hybrid and intra-cloud connectivity approaches.

Option	Best For	Strengths	Weaknesses	When to Choose
AWS Site-to-Site VPN	Hybrid connectivity over internet	Fast to deploy, encrypted, managed AWS endpoint, two tunnels	Variable internet performance, device config complexity	Quick hybrid connectivity, branch connectivity, DX backup
AWS Direct Connect	Dedicated private connectivity	Predictable performance, lower latency variability, private circuit	Lead time, cost, colocation/partner dependency	Mission-critical connectivity, consistent throughput/latency
AWS Client VPN	Remote user access	Managed client VPN for users	Not meant for site routers; user/device management	Workforce access to VPC/private apps
AWS Transit Gateway (without VPN)	VPC-to-VPC routing	Scalable hub routing inside AWS	Doesn’t connect on-prem by itself	Multi-VPC architecture within AWS
VPC Peering	Simple VPC-to-VPC connectivity	Low latency, simple	Non-transitive, route limits, scaling complexity	Small number of VPCs needing direct connectivity
Self-managed IPsec on EC2	Custom VPN needs	Full control	You manage availability, scaling, patching	Niche cases where managed VPN doesn’t fit
Azure VPN Gateway	Hybrid to Azure	Similar managed model	Cloud-specific	If your workloads are in Azure
Google Cloud VPN	Hybrid to GCP	Similar managed model	Cloud-specific	If your workloads are in GCP
Third-party SD-WAN	Many sites, advanced routing/policy	Central policy, app-aware routing	Cost/complexity, vendor lock-in	Large branch networks with advanced needs

15. Real-World Example

Enterprise example: Retail chain with hundreds of stores

Problem: Stores need secure access to centrally hosted applications in AWS, plus segmented access to payment systems. MPLS is expensive and slow to expand.
Proposed architecture:
Transit Gateway in primary Region
Site-to-Site VPN from each store SD-WAN/router into TGW (two tunnels per connection)
TGW route tables segment:
- Store-to-app routes
- Store-to-payment routes (restricted)
Centralized inspection VPC with firewalls for egress control
CloudWatch alarms on tunnel state, Network Manager for visibility (verify features)
Why AWS Site-to-Site VPN was chosen:
Fast rollout to many sites using existing internet links
Standard IPsec compatibility with branch routers
Works well as an overlay even when some sites later adopt Direct Connect through hubs
Expected outcomes:
Rapid onboarding of stores
Encrypted connectivity and consistent segmentation
Centralized operations and alerting

Startup/small-team example: Hybrid SaaS migration

Problem: A startup has a legacy on-prem database and wants to move app servers to AWS quickly without exposing the database publicly.
Proposed architecture:
Single VPC with VGW
One AWS Site-to-Site VPN to the office firewall
App servers in private subnets; database remains on-prem temporarily
Why AWS Site-to-Site VPN was chosen:
Low operational overhead compared to building VPN appliances
Enough bandwidth and security for phased migration
Expected outcomes:
Private connectivity for app-to-db
Faster migration without re-architecting networking upfront
Simple rollback path during cutover

16. FAQ

1) Is AWS Site-to-Site VPN the same as AWS Client VPN?

No. AWS Site-to-Site VPN connects networks (site routers/firewalls) to AWS. AWS Client VPN connects individual users/devices to AWS.

2) Does one VPN connection include two tunnels?

Yes. A standard AWS Site-to-Site VPN connection includes two tunnels for redundancy.

3) Can I use BGP with AWS Site-to-Site VPN?

Yes, dynamic routing with BGP is supported when you select dynamic routing and configure ASNs appropriately.

4) Should I choose static routes or BGP?

Choose BGP for resilience and easier route management at scale.
Choose static for small/simple networks or where BGP is not possible.

5) Does AWS manage my on-prem device?

No. AWS manages the AWS endpoint (VGW/TGW side). You manage the customer gateway device configuration and operations.

6) Can I connect multiple VPCs to one on-prem network?

Yes—best done using AWS Transit Gateway (hub-and-spoke). With VGW, it’s more limited and often becomes complex.

7) Can I use AWS Site-to-Site VPN as backup for Direct Connect?

Yes. This is a common design pattern for resiliency.

8) Why are my tunnels UP but traffic doesn’t flow?

Common causes: – Missing routes (VPC route table / on-prem routes) – Security groups/NACLs blocking traffic – Source/destination check not disabled on a routing instance – Overlapping CIDRs

9) Do I need an internet gateway in my VPC to use Site-to-Site VPN?

Not for the VPC’s private subnets to use the VPN. But your on-prem customer gateway must have internet reachability to establish tunnels to AWS public endpoints.

10) How do I monitor tunnel health?

Use CloudWatch metrics/alarms for tunnel state and throughput, and monitor customer gateway device logs for IKE/IPsec events.

11) Are VPN tunnels encrypted end-to-end?

Traffic between gateways is encrypted with IPsec. Inside your networks (within VPC or within on-prem), traffic is routed normally unless you add additional encryption.

12) Can I restrict which subnets can use the VPN?

Yes. Use VPC route tables (associate only certain subnets) and security groups/NACLs.

13) What happens during rekeying?

IPsec rekeys are normal. Some devices handle them differently and may cause brief disruption; test under load and follow AWS/vendor recommended settings.

14) Can I use the same customer gateway for multiple VPN connections?

Yes, you can define multiple VPN connections to the same customer gateway device if needed, but consider operational complexity and routing design.

15) Is AWS Site-to-Site VPN suitable for high-throughput, low-latency applications?

Sometimes, but the internet path is variable. For strict performance requirements, consider AWS Direct Connect, or test acceleration options (verify current performance guidance in official docs).

16) Can I connect to a Transit Gateway instead of a VPC?

Yes. AWS Site-to-Site VPN can terminate on a Transit Gateway VPN attachment (recommended for multi-VPC architectures).

17) Do I need to open inbound ports to my on-prem network?

Your customer gateway must accept IKE/IPsec negotiation from AWS tunnel endpoints. That usually means allowing UDP 500/4500 (and sometimes ESP) to the gateway.

17. Top Online Resources to Learn AWS Site-to-Site VPN

Resource Type	Name	Why It Is Useful
Official documentation	AWS Site-to-Site VPN User Guide	Primary, authoritative reference for concepts, configuration, and operations: https://docs.aws.amazon.com/vpn/latest/s2svpn/what-is-vpn.html
Official documentation	Amazon VPC User Guide (VGW/VPN sections)	Explains VPC routing, gateways, and hybrid networking: https://docs.aws.amazon.com/vpc/latest/userguide/
Official documentation	AWS Transit Gateway documentation	Required if you terminate VPN on TGW: https://docs.aws.amazon.com/vpc/latest/tgw/what-is-transit-gateway.html
Official pricing	AWS VPN Pricing	Current pricing dimensions and Region-specific info: https://aws.amazon.com/vpn/pricing/
Official calculator	AWS Pricing Calculator	Build realistic cost estimates: https://calculator.aws/
Official quotas	Amazon VPC limits / Service Quotas	Understand quotas and request increases: https://docs.aws.amazon.com/vpc/latest/userguide/amazon-vpc-limits.html
Official monitoring	Amazon CloudWatch	Metrics and alarms for VPN tunnel telemetry (verify specific metrics in docs): https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/WhatIsCloudWatch.html
Official audit logging	AWS CloudTrail	Track control-plane changes to VPN resources: https://docs.aws.amazon.com/awscloudtrail/latest/userguide/cloudtrail-user-guide.html
Architecture guidance	AWS Architecture Center	Patterns for hybrid networking and multi-VPC design: https://aws.amazon.com/architecture/
Reference architectures	AWS Prescriptive Guidance (Networking)	Practical guidance for enterprise networking patterns: https://docs.aws.amazon.com/prescriptive-guidance/latest/networking/
Workshops/labs	AWS Workshops (search for networking/VPN/TGW)	Hands-on labs; content varies over time: https://workshops.aws/
Videos	AWS YouTube channel	Talks and re:Invent sessions on hybrid networking: https://www.youtube.com/@AmazonWebServices
Community (highly used)	strongSwan Documentation	Device-side implementation details for Linux VPN endpoints: https://docs.strongswan.org/

18. Training and Certification Providers

DevOpsSchool.com – Suitable audience: DevOps engineers, SREs, cloud engineers, platform teams – Likely learning focus: AWS operations, DevOps tooling, cloud networking fundamentals – Mode: check website – Website: https://www.devopsschool.com/
ScmGalaxy.com – Suitable audience: Developers, DevOps beginners, build/release engineers – Likely learning focus: SCM, CI/CD, DevOps foundations that complement cloud networking – Mode: check website – Website: https://www.scmgalaxy.com/
CLoudOpsNow.in – Suitable audience: CloudOps engineers, operations teams, junior-to-mid cloud practitioners – Likely learning focus: Cloud operations, monitoring, reliability, and cloud infrastructure practices – Mode: check website – Website: https://www.cloudopsnow.in/
SreSchool.com – Suitable audience: SREs, production engineering, reliability-focused teams – Likely learning focus: Reliability engineering, observability, incident response practices relevant to hybrid connectivity – Mode: check website – Website: https://www.sreschool.com/
AiOpsSchool.com – Suitable audience: Operations teams adopting AIOps, monitoring and automation practitioners – Likely learning focus: AIOps concepts, automation, operational analytics that can complement network monitoring – Mode: check website – Website: https://www.aiopsschool.com/

19. Top Trainers

RajeshKumar.xyz – Likely specialization: DevOps and cloud training content (verify exact offerings on site) – Suitable audience: Beginners to practitioners seeking practical guidance – Website: https://rajeshkumar.xyz/
devopstrainer.in – Likely specialization: DevOps tooling and cloud-oriented training (verify exact offerings on site) – Suitable audience: DevOps engineers and cloud learners – Website: https://www.devopstrainer.in/
devopsfreelancer.com – Likely specialization: DevOps consulting/training style resources (verify exact offerings on site) – Suitable audience: Teams or individuals looking for practical implementation help – Website: https://www.devopsfreelancer.com/
devopssupport.in – Likely specialization: DevOps support and training resources (verify exact offerings on site) – Suitable audience: Operations and DevOps teams needing hands-on support – Website: https://www.devopssupport.in/

20. Top Consulting Companies

cotocus.com – Likely service area: Cloud and DevOps consulting (verify service catalog on site) – Where they may help: Cloud migration planning, infrastructure automation, operations setup – Consulting use case examples: – Hybrid connectivity planning (VPN/DX) and routing design review – VPC/TGW architecture and segmentation guidance – Cost optimization for network egress and connectivity – Website: https://cotocus.com/
DevOpsSchool.com – Likely service area: DevOps and cloud consulting/training services (verify on site) – Where they may help: Training + implementation support for cloud infrastructure and operations – Consulting use case examples: – Building standardized connectivity patterns across environments – Implementing monitoring/alerting for VPN tunnel health – Creating runbooks and operational readiness for hybrid networks – Website: https://www.devopsschool.com/
DEVOPSCONSULTING.IN – Likely service area: DevOps consulting services (verify on site) – Where they may help: DevOps transformation, cloud operations, automation – Consulting use case examples: – Infrastructure-as-code patterns for networking resources – Security reviews for hybrid connectivity and IAM boundaries – Production readiness checks for VPN-based connectivity – Website: https://www.devopsconsulting.in/

21. Career and Learning Roadmap

Job roles that use it

Cloud Network Engineer
Solutions Architect
Platform Engineer
SRE / Production Engineer
Security Engineer (network/security boundary designs)

Certification path (AWS)

AWS certifications change over time; verify current paths on AWS Training & Certification. Relevant tracks often include: – AWS Certified Solutions Architect (Associate/Professional) – AWS Certified Advanced Networking – Specialty (if available; verify current status) Official portal: https://aws.amazon.com/certification/

Project ideas for practice

Build a TGW hub-and-spoke with two VPCs and one VPN site; implement segmentation with TGW route tables.
Implement VPN + Direct Connect backup design (simulate DX routing logic with lab constructs; validate failover behavior carefully).
Create CloudWatch alarms and an operational dashboard for tunnel state and traffic metrics.
Write Terraform to deploy VGW/TGW VPN patterns with consistent tagging and naming.

22. Glossary

AWS Site-to-Site VPN: Managed AWS service that provides IPsec VPN tunnels between your network and AWS.
IPsec: Suite of protocols for encrypting and authenticating IP packets.
IKE (Internet Key Exchange): Protocol used to set up security associations for IPsec.
Tunnel: Encrypted path between two VPN endpoints.
VGW (Virtual Private Gateway): AWS-managed VPN endpoint for a single VPC.
TGW (Transit Gateway): AWS-managed hub router for connecting VPCs and on-prem networks.
Customer Gateway (CGW): AWS resource representing your on-prem VPN endpoint (public IP, ASN).
BGP: Dynamic routing protocol used to exchange routes and enable resilient routing.
Static routes: Manually configured network prefixes for routing over the VPN.
Route table: Set of routing rules that determines where network traffic is directed.
Security group: Stateful virtual firewall attached to ENIs/instances in a VPC.
Network ACL (NACL): Stateless subnet-level firewall.
Elastic IP (EIP): Static public IPv4 address in AWS.
Source/destination check: EC2 feature that must be disabled on instances that forward traffic like routers.
CIDR: Notation for IP prefixes (e.g., 10.0.0.0/16).

23. Summary

AWS Site-to-Site VPN (AWS) is a managed Networking and content delivery service that provides encrypted IPsec connectivity between your on-premises network (customer gateway) and AWS (VGW or TGW). It matters because it enables fast, secure hybrid networking with built-in redundancy (two tunnels per connection) and flexible routing (static or BGP).

Cost is primarily driven by VPN connection hours, data transfer, and (in scaled designs) Transit Gateway charges. Security outcomes depend on correct IPsec parameters, strict IAM control, secure PSK handling, and careful routing/segmentation.

Use AWS Site-to-Site VPN when you need quick hybrid connectivity, branch connectivity, or a backup path for Direct Connect. For strict performance requirements, evaluate Direct Connect and test designs under realistic traffic. Next, deepen your skills by learning Transit Gateway routing and building standardized, monitored hybrid patterns using IaC.

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