Cloud VPN for hybrid connectivity in GCP - Mini Project: Build & Apply

Cloud VPN for hybrid connectivity

📖 Scenario: You work for a company that has an on-premises data center and wants to securely connect it to their Google Cloud environment. To do this, they want to set up a Cloud VPN tunnel that allows private communication between the two networks.

🎯 Goal: Build a Cloud VPN setup in Google Cloud Platform that connects a Virtual Private Cloud (VPC) network to an on-premises network using a VPN gateway and tunnel.

📋 What You'll Learn

Create a VPC network named hybrid-vpc with a subnet hybrid-subnet in region us-central1 with IP range 10.10.0.0/16.

Create a Cloud VPN gateway named hybrid-vpn-gateway in us-central1 attached to the hybrid-vpc network.

Create a VPN tunnel named hybrid-vpn-tunnel connecting the Cloud VPN gateway to the on-premises VPN gateway IP 203.0.113.1 using IKEv2 and shared secret mysecret123.

Configure the VPN tunnel to route traffic to the on-premises subnet 192.168.100.0/24.

💡 Why This Matters

🌍 Real World

Many companies use Cloud VPN to securely connect their existing on-premises networks to their cloud environments, enabling hybrid cloud architectures.

💼 Career

Understanding how to configure Cloud VPN is essential for cloud engineers and network administrators managing hybrid cloud connectivity.

1

Create the VPC network and subnet

Create a VPC network called hybrid-vpc with a subnet named hybrid-subnet in region us-central1 with IP range 10.10.0.0/16 using gcloud commands.

GCP

# Your code here to create VPC network and subnet

Hint

Use gcloud compute networks create with --subnet-mode=custom to create the VPC. Then create the subnet with gcloud compute networks subnets create.

2

Create the Cloud VPN gateway

Create a Cloud VPN gateway named hybrid-vpn-gateway in region us-central1 attached to the hybrid-vpc network using gcloud commands.

GCP

gcloud compute networks create hybrid-vpc --subnet-mode=custom

gcloud compute networks subnets create hybrid-subnet --network=hybrid-vpc --region=us-central1 --range=10.10.0.0/16
# Your code here to create Cloud VPN gateway

Hint

Use gcloud compute vpn-gateways create with the network and region flags.

3

Create the VPN tunnel

Create a VPN tunnel named hybrid-vpn-tunnel connecting the Cloud VPN gateway hybrid-vpn-gateway to the on-premises VPN gateway IP 203.0.113.1 using IKEv2 and shared secret mysecret123 in region us-central1 with traffic selector for subnet 192.168.100.0/24.

GCP

gcloud compute networks create hybrid-vpc --subnet-mode=custom

gcloud compute networks subnets create hybrid-subnet --network=hybrid-vpc --region=us-central1 --range=10.10.0.0/16

gcloud compute vpn-gateways create hybrid-vpn-gateway --network=hybrid-vpc --region=us-central1
# Your code here to create VPN tunnel

Hint

Use gcloud compute vpn-tunnels create with the VPN gateway, peer address, IKE version, shared secret, and traffic selectors.

4

Add route for on-premises subnet

Create a static route named route-to-onprem in the hybrid-vpc network that directs traffic to the on-premises subnet 192.168.100.0/24 through the VPN tunnel hybrid-vpn-tunnel.

GCP

gcloud compute networks create hybrid-vpc --subnet-mode=custom

gcloud compute networks subnets create hybrid-subnet --network=hybrid-vpc --region=us-central1 --range=10.10.0.0/16

gcloud compute vpn-gateways create hybrid-vpn-gateway --network=hybrid-vpc --region=us-central1

gcloud compute vpn-tunnels create hybrid-vpn-tunnel --region=us-central1 --vpn-gateway=hybrid-vpn-gateway --peer-address=203.0.113.1 --ike-version=2 --shared-secret=mysecret123 --local-traffic-selector=10.10.0.0/16 --remote-traffic-selector=192.168.100.0/24
# Your code here to create route

Hint

Use gcloud compute routes create with the network, destination range, and next hop VPN tunnel details.

Practice

1. What is the primary purpose of Cloud VPN in a hybrid cloud setup?

easy

A. To securely connect your local network to your cloud network over the internet

B. To store data backups in the cloud

C. To monitor cloud resource usage

D. To create virtual machines in the cloud

Solution

1. Step 1: Understand Cloud VPN function

   Cloud VPN creates a secure connection between local and cloud networks over the internet.

2. Step 2: Identify the main use case

   It is used to link networks privately, not for storage, monitoring, or VM creation.

3. Final Answer:

   To securely connect your local network to your cloud network over the internet -> Option A

4. Quick Check:

   Cloud VPN = secure hybrid network link [OK]

Hint: Cloud VPN links networks securely over internet [OK]

Common Mistakes:

• Confusing VPN with storage or monitoring services
• Thinking VPN creates cloud resources
• Assuming VPN is for data backup only

2. Which of the following is the correct way to specify the shared secret in a Cloud VPN tunnel configuration?

easy

A. shared-secret: mySecret123

B. shared_secret = mySecret123

C. secretShared: 'mySecret123'

D. sharedSecret: "mySecret123"

Solution

1. Step 1: Review Cloud VPN tunnel config syntax

   The shared secret is specified as a key-value pair with key 'sharedSecret' and a string value.

2. Step 2: Match correct syntax

   sharedSecret: "mySecret123" uses correct key and quotes for the secret string, matching expected config format.

3. Final Answer:

   sharedSecret: "mySecret123" -> Option D

4. Quick Check:

   Correct key and quotes for shared secret [OK]

Hint: Use exact key 'sharedSecret' with quotes [OK]

Common Mistakes:

• Using underscores or hyphens incorrectly in key names
• Omitting quotes around the secret string
• Swapping key name order

3. Given this Cloud VPN tunnel configuration snippet:

localTrafficSelector: ["10.0.0.0/24"]
remoteTrafficSelector: ["192.168.1.0/24"]

What traffic will be routed through the VPN tunnel?

medium

A. Only traffic within 192.168.1.0/24 subnet

B. All traffic from 10.0.0.0/24 to any IP

C. Traffic from 10.0.0.0/24 to 192.168.1.0/24 and vice versa

D. Traffic from 192.168.1.0/24 to 10.0.0.0/24 only

Solution

1. Step 1: Understand traffic selectors

   LocalTrafficSelector defines local IP ranges; remoteTrafficSelector defines remote IP ranges for the tunnel.

2. Step 2: Determine routed traffic

   Traffic between these two IP ranges (10.0.0.0/24 and 192.168.1.0/24) is routed through the VPN tunnel.

3. Final Answer:

   Traffic from 10.0.0.0/24 to 192.168.1.0/24 and vice versa -> Option C

4. Quick Check:

   Traffic between local and remote selectors routed [OK]

Hint: Traffic between local and remote selectors goes through VPN [OK]

Common Mistakes:

• Assuming all local traffic routes through VPN
• Confusing direction of traffic routing
• Ignoring remote traffic selector

4. You configured a Cloud VPN tunnel but the connection fails. Which of these is a common misconfiguration to check?

medium

A. Mismatched shared secret between local and cloud VPN gateways

B. Incorrect VM instance size in cloud

C. Missing firewall rule allowing HTTP traffic

D. Using a public IP address for the local network

Solution

1. Step 1: Identify common VPN tunnel failure causes

   Mismatched shared secrets prevent tunnel establishment as authentication fails.

2. Step 2: Evaluate other options

   VM size and HTTP firewall rules do not affect VPN tunnel setup; local network uses private IPs, not public IPs.

3. Final Answer:

   Mismatched shared secret between local and cloud VPN gateways -> Option A

4. Quick Check:

   Shared secret mismatch breaks VPN tunnel [OK]

Hint: Check shared secret matches on both sides [OK]

Common Mistakes:

• Ignoring shared secret mismatch
• Checking unrelated VM or firewall settings
• Confusing public and private IP usage

5. You want to connect your on-premises network (10.10.0.0/16) to your GCP VPC network (10.20.0.0/16) using Cloud VPN. Which setup step is essential to avoid routing conflicts?

hard

A. Assign public IPs to all on-premises devices

B. Ensure on-premises and VPC IP ranges do not overlap

C. Disable firewall rules on both sides

D. Use the same IP range for both networks for simplicity

Solution

1. Step 1: Understand IP range requirements for VPN

   Overlapping IP ranges cause routing confusion and packet loss between networks.

2. Step 2: Identify best practice

   Assign distinct, non-overlapping IP ranges to on-premises and cloud networks to ensure clear routing.

3. Final Answer:

   Ensure on-premises and VPC IP ranges do not overlap -> Option B

4. Quick Check:

   Non-overlapping IP ranges prevent routing conflicts [OK]

Hint: Avoid overlapping IP ranges for VPN networks [OK]

Common Mistakes:

• Using overlapping IP ranges causing routing issues
• Disabling firewalls unnecessarily
• Assigning public IPs to private network devices