main.tf

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "4.8.0"
    }
  }
}

provider "aws" {
  region = "us-east-1"
  #Using credentials file
  shared_credentials_files = ["credentials"]
  profile                  = "default"
}

### Networking
resource "aws_vpc" "main-vpc" {
  cidr_block = "10.0.0.0/16"
}

resource "aws_internet_gateway" "igw-1" {
  vpc_id = aws_vpc.main-vpc.id
  tags = {
    Name = "Internet Gateway 1"
  }
}

resource "aws_subnet" "publicsubnet1" { # Creating Public Subnets
  vpc_id            = aws_vpc.main-vpc.id
  cidr_block        = "10.0.0.0/24" # CIDR block of public subnets
  availability_zone = "us-east-1a"
  tags = {
    Name = "public-subnet-1"
  }
}

resource "aws_subnet" "privatesubnet1" { # Creating Private Subnets
  vpc_id            = aws_vpc.main-vpc.id
  cidr_block        = "10.0.1.0/24" # CIDR block of private subnets
  availability_zone = "us-east-1a"
  tags = {
    Name = "private-subnet-1"
  }
}

resource "aws_eip" "nateIP" {
  vpc = true
}

resource "aws_nat_gateway" "NATgw" {
  allocation_id = aws_eip.nateIP.id
  subnet_id     = aws_subnet.publicsubnet1.id
  tags = {
    Name = "nat-gw-1"
  }
}

resource "aws_route_table" "PublicRT" { # Creating RT for Public Subnet
  vpc_id = aws_vpc.main-vpc.id
  route {
    cidr_block = "0.0.0.0/0" # Traffic from Public Subnet reaches Internet via Internet Gateway
    gateway_id = aws_internet_gateway.igw-1.id
  }
  tags = {
    Name = "public-route-table"
  }
}

resource "aws_route_table" "PrivateRT" { # Creating RT for Private Subnet
  vpc_id = aws_vpc.main-vpc.id
  route {
    cidr_block     = "0.0.0.0/0" # Traffic from Private Subnet reaches Internet via NAT Gateway
    nat_gateway_id = aws_nat_gateway.NATgw.id
  }
  tags = {
    Name = "private-route-table-1"
  }
}

resource "aws_route_table_association" "PublicRTassociation1" {
  subnet_id      = aws_subnet.publicsubnet1.id
  route_table_id = aws_route_table.PublicRT.id
}

resource "aws_route_table_association" "PrivateRTassociation1" {
  subnet_id      = aws_subnet.privatesubnet1.id
  route_table_id = aws_route_table.PrivateRT.id
}