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Latchu@DevOps
Latchu@DevOps

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Part-59: Google Cloud Networking – Cloud NAT in GCP

#googlecloud #vpc #cloud #learning

When workloads in private subnets need outbound access (e.g., to the internet, APIs, or other networks) but should not expose a public IP, Google Cloud provides Cloud NAT (Network Address Translation).

Cloud NAT allows secure, scalable, and managed outbound connectivity without needing proxy VMs or public IPs on individual instances.

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🔹 What is Cloud NAT?

  • Cloud NAT primarily provides outbound connections for private resources.
  • It enables instances in a private subnet to connect to resources outside your VPC network.

Cloud NAT can be used with:

  • Compute Engine VM Instances (without public IPs)
  • Private GKE clusters
  • Cloud Run / Cloud Functions / App Engine (via Serverless VPC Access)

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🔹 Cloud NAT Types

1️⃣ Public NAT

  • Allows Google Cloud resources without public IPs to connect to the internet.
  • Uses a set of shared public IP addresses for outbound connections.
  • No proxy VMs – Google’s NAT gateway automatically manages IPs and ports.
  • Example use case: Private VM accessing apt-get package updates from the internet.

2️⃣ Private NAT

  • Enables private-to-private translation across Google Cloud networks.
  • Useful for VPC-to-VPC connectivity using Network Connectivity Center.
  • Example use case: VM in VPC-A talks to VM in VPC-B using private IPs, while keeping network isolation.

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🔹 Cloud NAT Benefits

✅ Security

  • Reduces need for external IPs per VM.
  • Fewer firewall rules to manage.

✅ Availability

  • Fully managed, distributed service.
  • No physical NAT VMs or single points of failure.

✅ Scalability

  • Can auto-scale NAT IPs and ports as traffic grows.

✅ Performance

  • No bandwidth throttling per VM.
  • Powered by Google’s Andromeda SDN (software-defined networking).

✅ Logging & Monitoring

  • NAT logs available for compliance, debugging, analytics, and accounting.
  • Exposes key metrics to Cloud Monitoring for visibility.

✅ Summary

  • Cloud NAT = Outbound connectivity for private workloads (VMs, GKE, Serverless).
  • Public NAT = Private resources → Internet.
  • Private NAT = Private resources → Other VPC networks.
  • Fully managed, scalable, and integrated with Cloud Monitoring & Logging.

Using Cloud NAT, you can build secure and scalable architectures without assigning public IPs to every VM. 🚀

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