Cloud VPN for hybrid connectivity in GCP - Step-by-Step Execution

Process Flow - Cloud VPN for hybrid connectivity

Start: On-premises Network

↓

Create VPN Gateway on GCP

↓

Create VPN Gateway on On-premises

↓

Establish VPN Tunnel

↓

Encrypt Traffic

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Send Data Securely

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Receive Data

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End: Hybrid Connectivity Established

This flow shows how a secure VPN tunnel is created between on-premises and GCP networks to enable hybrid connectivity.

Execution Sample

GCP

gcloud compute vpn-gateways create my-gcp-vpn --network my-vpc --region us-central1

gcloud compute vpn-tunnels create my-vpn-tunnel \
  --peer-address ON_PREM_PUBLIC_IP \
  --ike-version 2 \
  --shared-secret "mysecret" \
  --vpn-gateway my-gcp-vpn \
  --region us-central1

This code creates a VPN gateway and a VPN tunnel on GCP to connect to an on-premises VPN gateway.

Process Table

Step	Action	Input/Config	Result	Notes
1	Create VPN Gateway on GCP	Name: my-gcp-vpn, Network: my-vpc, Region: us-central1	VPN Gateway 'my-gcp-vpn' created	Gateway ready to accept tunnels
2	Create VPN Tunnel	Peer IP: ON_PREM_PUBLIC_IP, IKE version: 2, Shared Secret: 'mysecret', Gateway: my-gcp-vpn	VPN Tunnel 'my-vpn-tunnel' created	Tunnel ready to establish connection
3	On-premises VPN Gateway Setup	Configured with GCP VPN Gateway IP and shared secret	Tunnel established	Secure encrypted tunnel active
4	Traffic Encryption	Data packets from on-premises	Encrypted packets sent through tunnel	Data secured in transit
5	Data Transmission	Encrypted packets received by GCP VPN Gateway	Packets decrypted and forwarded to VPC	Hybrid connectivity active
6	Exit	N/A	Hybrid connectivity established	VPN tunnel active and data flows securely

💡 VPN tunnel established and hybrid connectivity is active, enabling secure communication between on-premises and GCP.

Status Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	After Step 5	Final
VPN Gateway Status	Not created	Created	Created	Created	Created	Created	Active
VPN Tunnel Status	Not created	Not created	Created	Established	Established	Established	Active
Traffic Encryption	None	None	None	None	Encrypting	Encrypted	Encrypted
Data Flow	None	None	None	None	Sending encrypted data	Receiving decrypted data	Secure flow

Key Moments - 3 Insights

Why do we need to create VPN gateways on both GCP and on-premises?

VPN gateways on both sides create endpoints for the VPN tunnel. Without both, the tunnel cannot be established (see execution_table steps 1 and 3).

What ensures the data is secure when sent over the internet?

The VPN tunnel encrypts data packets before sending (execution_table step 4), so data is protected during transit.

What happens if the shared secret does not match on both sides?

The tunnel will fail to establish because both sides must use the same shared secret for authentication (refer to step 3).

Visual Quiz - 3 Questions

Look at the execution table, at which step is the VPN tunnel created on GCP?

A Step 1

B Step 2

C Step 3

D Step 4

💡 Hint

Check the 'Action' column for 'Create VPN Tunnel' in the execution_table.

According to the variable tracker, when does traffic encryption start?

A After Step 4

B After Step 3

C After Step 2

D After Step 5

💡 Hint

Look at the 'Traffic Encryption' row in variable_tracker to see when it changes from 'None' to 'Encrypting'.

If the shared secret is incorrect, which step in the execution_table would fail?

A Step 1

B Step 2

C Step 3

D Step 5

💡 Hint

Refer to step 3 where the tunnel is established and shared secret is verified.

Concept Snapshot

Cloud VPN connects on-premises and GCP networks securely.
Create VPN gateways on both sides.
Set up VPN tunnel with shared secret and IKE version.
Tunnel encrypts data for secure transmission.
Hybrid connectivity enables private communication over the internet.

Full Transcript

Cloud VPN for hybrid connectivity involves creating VPN gateways on both Google Cloud and on-premises networks. Then, a VPN tunnel is established between these gateways using a shared secret and IKE version 2. This tunnel encrypts data traffic, ensuring secure communication over the public internet. Once the tunnel is active, data flows securely between the two networks, enabling hybrid cloud scenarios.

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