Update main.tf

external-network/main.tf

-variable "admin_state_up" {default = "string" }
-variable "public_network_name" {default = "string" }
-variable "enable_dhcp" {default = "string"}
+variable "admin_state_up" {}
+variable "public_network_name" {}
+variable "enable_dhcp" {}
 variable "name" {default = "dmz"}
 
 data "openstack_networking_network_v2" "public-network" {name = "bright-external-flat-externalnet"}