Terraform + Localstack

main.tf

provider "aws" {
  region = "us-west-2"
  access_key = "anaccesskey"
  secret_key = "asecretkey"
  skip_credentials_validation = true
  skip_metadata_api_check = true
  s3_force_path_style = true
  endpoints {
    s3 = "http://119.18.0.101:4572"
  }
}

resource "aws_s3_bucket" "b" {
  bucket = "my-tf-test-bucket"
  acl    = "public-read"
}

outputs.tf

output "address" {
  value = "${aws_s3_bucket.b.bucket}"
}

variables.tf

variable "aws_region" {
  description = "AWS region to launch servers."
  default     = "us-west-2"
}

variable "key_name" {
  description = "Name of the SSH keypair to use in AWS."
  default     = "deployer-ley"
}

variable "key_path" {
  description = "Path to the private portion of the SSH key specified."
  default     = "~/pem.pem"
}

Why I should set up s3 endpoint to 119.18.0.101 in main.tf line 9?
It's not a reserved ip address.