Terraform VPC and Network Creation Guide: Subnets, Routes, and Security Groups

Terraform VPC and Network Creation Guide#

Learn how to design and create cloud networking with Terraform, including VPCs, virtual networks, subnets, routes, security groups, and reusable modules.

Network building blocks#

• VPC or virtual network.
• Public and private subnets.
• Route tables.
• Internet gateway or NAT gateway.
• Security groups or network security groups.
• DNS and private endpoints where required.

Example AWS VPC resource#

resource "aws_vpc" "main" { cidr_block = "10.0.0.0/16" enable_dns_hostnames = true tags = { Name = "demo-vpc" } }

Example subnet#

resource "aws_subnet" "public" { vpc_id = aws_vpc.main.id cidr_block = "10.0.1.0/24" }

Best practices#

• Plan CIDR ranges before writing Terraform.
• Separate public and private subnets.
• Use modules for repeatable network patterns.
• Use clear names and tags.
• Do not expose private services publicly.

Related guides#

• Terraform Learning Path
• Terraform Modules Explained