1️⃣ NAT Gateway

🔹 Definition

NAT Gateway provides outbound-only internet access for private subnets.

• No inbound traffic allowed
• Stable, static outbound IP
• More secure than public IPs on VMs

When to use

• Private VMs need to download updates
• Backend services calling external APIs

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🔧 Azure CLI (Basic)

az network nat gateway create \
  --resource-group rg-vnet-demo \
  --name nat-gateway \
  --public-ip-addresses nat-ip \
  --idle-timeout 10

Attach to subnet:

az network vnet subnet update \
  --resource-group rg-vnet-demo \
  --vnet-name vnet-main \
  --name subnet-private \
  --nat-gateway nat-gateway

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🖥️ Azure Portal Flow

Portal → NAT Gateway → Create
→ Select Resource Group
→ Attach Public IP
→ Attach to Private Subnet

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📦 Example

Private VM → NAT Gateway → Internet
Internet ❌→ Private VM

✔ Outbound allowed ❌ Inbound blocked

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