diff --git a/README.md b/README.md
index b0738a5..ddae4cb 100644
--- a/README.md
+++ b/README.md
@@ -304,7 +304,7 @@ Question and Answer
 
 [GKE assigns a separate IP address to each `Ingress`](https://cloud.google.com/kubernetes-engine/docs/concepts/ingress#limitations), but we can have a single `Gateway` with an IP address and then any quantity of `HTTPRoute`. This is a design choice for GKE, and not a limitation of kubernetes.
 
-If you need to use `Ingress`, we can achieve the same efficiency for IP addresses by using the nginx ingress controller. This can be enabled by passing `-var ingress_type=nginx`.
+If you need to use `Ingress`, we can achieve the same efficiency for IP addresses by using the nginx ingress controller. This can be enabled by passing `-var ingress_type=nginx`. If you need to use the built-in ingress controller instead of nginx you can set `-var ingress_type=gce` but then each `Ingress` will cost 1 IP address.
 
 Clean Up
 ========
diff --git a/terraform/main.tf b/terraform/main.tf
index 2e63407..485b2dd 100644
--- a/terraform/main.tf
+++ b/terraform/main.tf
@@ -1,3 +1,4 @@
+# TODO: put IP address ranges into variables
 terraform {
   backend "gcs" {
     bucket = "tf-state-4b00"
@@ -50,8 +51,8 @@ variable "ingress_type" {
   default     = "gateway"
 
   validation {
-    condition     = contains(["gateway", "nginx"], var.ingress_type)
-    error_message = "Must be either \"gateway\" or \"nginx\"."
+    condition     = contains(["gateway", "nginx", "gce"], var.ingress_type)
+    error_message = "Must be either \"gateway\", \"nginx\", or \"gce\"."
   }
 }