What is Cloud NAT in GCP: Simple Explanation and Use Cases

Cloud NAT in GCP is a managed service that lets private virtual machines access the internet securely without exposing their internal IP addresses. It translates private IPs to public IPs for outbound connections, keeping your resources safe and reachable only from inside your network.

How It Works

Imagine your private virtual machines (VMs) as people inside a house with no direct door to the outside world. They need to send letters (data) outside but don’t want strangers to know their home address. Cloud NAT acts like a trusted post office that forwards these letters using its own public address, so the outside world only sees the post office, not the house.

Technically, Cloud NAT translates the private IP addresses of your VMs to public IP addresses when they connect to the internet. This allows your VMs to reach external services like software updates or APIs without having public IPs themselves. Incoming connections from the internet to these VMs are blocked, keeping them secure.

Example

This example shows how to create a Cloud NAT configuration for a GCP VPC network using gcloud CLI. It enables NAT for all VM instances in the specified region without public IPs.

bash

gcloud compute routers create nat-router --network default --region us-central1

gcloud compute routers nats create nat-config \
  --router=nat-router \
  --region=us-central1 \
  --nat-all-subnet-ip-ranges \
  --auto-allocate-nat-external-ips

Output

Created [https://www.googleapis.com/compute/v1/projects/PROJECT_ID/regions/us-central1/routers/nat-router].
Created [https://www.googleapis.com/compute/v1/projects/PROJECT_ID/regions/us-central1/routers/nat-router/nats/nat-config].

When to Use

Use Cloud NAT when you want your private VMs to access the internet without exposing their IP addresses. This is common for:

• Downloading software updates securely
• Accessing external APIs or services
• Running batch jobs that need internet access
• Keeping your infrastructure secure by avoiding public IPs on VMs

It is especially useful in environments where security and compliance require strict control over inbound traffic.

Key Points

• Cloud NAT provides outbound internet access for private VMs without public IPs.
• It hides VM IPs by translating them to shared public IPs.
• Inbound connections from the internet to VMs are blocked by default.
• It is fully managed by GCP, reducing operational overhead.

Key Takeaways

Cloud NAT enables private VMs to access the internet securely without public IPs.

It translates private IP addresses to public IPs for outbound connections only.

Use Cloud NAT to keep your infrastructure secure and compliant.

It is easy to set up and fully managed by Google Cloud.

Inbound internet traffic to private VMs remains blocked for safety.