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This page shows the required configuration for exposing an App Engine flexible environment
service only on its internal IP address.
By default, flexible environment services receive both an internal IP address
and an ephemeral external IP address when they are first deployed. The
ephemeral external IP address allows your service to send requests to
App Engine services with custom domains, and resources on the internet.
Ephemeral external IP addresses incur costs.
If your service does not require an external IP address, you can prevent your
service from sending requests to resources on the internet and reduce costs by
limiting your service to using only its internal IP address. This does not
prevent your service from receiving requests from the internet or
App Engine services with custom domains, because the fully qualified
domain name of your service is still externally visible.
Limitations
Disabling ephemeral external IP addresses has the following limitations:
Services with custom domains: To send requests to App Engine
services with custom domains you must
configure Cloud NAT.
External resources: To send requests to external resources you must
configure Cloud NAT.
Private Google Access dependency: Instances with IP mode set to
internal require
Private Google Access on
the target subnetwork.
Legacy networks:Legacy networks cannot use
Private Google Access, and thus cannot disable ephemeral external IP
addresses.
Before you begin
To deploy flexible environment apps without external IP addresses, you must
enable Private Google Access on the target subnetwork.
To learn about Private Google Access, see the Overview.
If you use Shared VPC, follow these steps to prepare your
Shared VPC network for further configuration.
Verify that you have a route that is compatible with
Private Google Access. Typically the
default route of a network is
compatible with Private Google Access. For other routes, confirm that
the route is configured as follows.
Network: SHARED_VPC_NETWORK_NAME
Destination IP address range: 0.0.0.0/0
Instance tags: INSTANCE_TAGS
Next hop: DEFAULT_INTERNET_GATEWAY
Replace the following:
SHARED_VPC_NETWORK_NAME: The name of your
Shared VPC network.
INSTANCE_TAGS: If you do not use any instance
tags, do not specify anything in this field. If you do use instance tags,
include aef-instances in your list of instance tags.
DEFAULT_INTERNET_GATEWAY: The default internet gateway.
To learn more about compatible routes for Private Google Access, see
the Private Google Access documentation on
routing options.
Verify that you have a firewall rule that is compatible with
Private Google Access. The firewall rule must be configured as
follows.
Network: SHARED_VPC_NETWORK_NAME
Destination IP address range: 0.0.0.0/0
Destination filter: IP ranges
Direction of traffic: Egress
Attach on match: Allow
Instance tags: INSTANCE_TAGS
Replace the following:
SHARED_VPC_NETWORK_NAME: The name of your
Shared VPC network.
INSTANCE_TAGS: If you do not use any instance
tags, do not specify anything in this field. If you do use instance tags,
include aef-instances in your list of instance tags.
To learn more about compatible firewall rules for
Private Google Access, see the Private Google Access
documentation on
firewall configuration.
Configure your service to use only its internal IP address
Update the Google Cloud CLI. This ensures that you are using a version of the
gcloud CLI that supports private IP addresses for
flexible environment apps.
gcloudcomponentsupdate
In your app.yaml file, add the instance_ip_mode field to the
network section
and set it to internal.
If your app.yaml file already has a network section, add the following
line inside the network section:
instance_ip_mode:internal
If your app.yaml file doesn't have a network section, create the
section and specify the instance IP mode by adding the following lines:
network:
instance_ip_mode:internal
Save these changes.
Deploy the service.
gcloudbetaappdeploy
Verify configuration by checking the Instances page of the Google Cloud console.
Scroll down to the Instances table (below the Summary chart). In the
External IP column, confirm that there is no IP address listed. The
absence of an IP address in this column means that your instance has no
external IP address. Even though this field is empty, your instance still has
an internal IP address.
Send external requests without an external IP address
If your service sends requests to the internet but you want to limit it to using
only its internal IP address, you can use Cloud NAT to
create a gateway. Your service can send external requests through the
Cloud NAT gateway without using the default ephemeral external IP addresses.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-29 UTC."],[[["\u003cp\u003eThis guide outlines how to configure an App Engine flexible environment service to use only its internal IP address, thus preventing it from sending requests to resources on the internet and reducing costs associated with ephemeral external IP addresses.\u003c/p\u003e\n"],["\u003cp\u003eDisabling ephemeral external IP addresses requires enabling Private Google Access on the target subnetwork and has limitations, including the necessity to configure Cloud NAT for services with custom domains or those sending requests to external resources.\u003c/p\u003e\n"],["\u003cp\u003eTo prepare a Shared VPC network, it's essential to verify compatibility with Private Google Access by confirming the presence of a compatible default route and a firewall rule configured for egress traffic.\u003c/p\u003e\n"],["\u003cp\u003eConfiguring the service involves updating the Google Cloud CLI, adding the \u003ccode\u003einstance_ip_mode: internal\u003c/code\u003e line in the \u003ccode\u003enetwork\u003c/code\u003e section of the \u003ccode\u003eapp.yaml\u003c/code\u003e file, deploying the updated service, and verifying the absence of an external IP address on the Instances page in the Google Cloud console.\u003c/p\u003e\n"],["\u003cp\u003eServices limited to internal IPs needing to send requests to the internet can do so via setting up a Cloud NAT gateway, which acts as an intermediary allowing communication without the service utilizing an ephemeral external IP.\u003c/p\u003e\n"]]],[],null,["# Configure private internal-only services\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\nThis page shows the required configuration for exposing an App Engine flexible environment\nservice only on its internal IP address.\n\nBy default, flexible environment services receive both an internal IP address\nand an ephemeral external IP address when they are first deployed. The\nephemeral external IP address allows your service to send requests to\nApp Engine services with custom domains, and resources on the internet.\nEphemeral external IP addresses incur [costs](/vpc/network-pricing#ipaddress).\n\nIf your service does not require an external IP address, you can prevent your\nservice from sending requests to resources on the internet and reduce costs by\nlimiting your service to using only its internal IP address. This does not\nprevent your service from receiving requests from the internet or\nApp Engine services with custom domains, because the fully qualified\ndomain name of your service is still externally visible.\n\nLimitations\n-----------\n\nDisabling ephemeral external IP addresses has the following limitations:\n\n- **Services with custom domains:** To send requests to App Engine services with custom domains you must [configure Cloud NAT](/nat/docs/set-up-manage-network-address-translation).\n- **External resources:** To send requests to external resources you must [configure Cloud NAT](/nat/docs/set-up-manage-network-address-translation).\n- **Private Google Access dependency:** Instances with IP mode set to `internal` require [Private Google Access](/vpc/docs/private-google-access#pga-supported) on the target subnetwork.\n- **Legacy networks:** [Legacy networks](/vpc/docs/legacy) cannot use Private Google Access, and thus cannot disable ephemeral external IP addresses.\n\nBefore you begin\n----------------\n\nTo deploy flexible environment apps without external IP addresses, you must\nenable Private Google Access on the target subnetwork.\n\n- To learn about Private Google Access, see the [Overview](/vpc/docs/private-google-access#pga-supported).\n- For step-by-step configuration instructions, see [Enabling Private Google Access](/vpc/docs/configure-private-google-access#enabling-pga).\n\n### Prepare your Shared VPC network\n\nIf you use Shared VPC, follow these steps to prepare your\nShared VPC network for further configuration.\n\n1. Verify that you have a route that is compatible with\n Private Google Access. Typically the\n [default route](/vpc/docs/routes#routingpacketsinternet) of a network is\n compatible with Private Google Access. For other routes, confirm that\n the route is configured as follows.\n\n ```sh\n Network: SHARED_VPC_NETWORK_NAME\n Destination IP address range: 0.0.0.0/0\n Instance tags: INSTANCE_TAGS\n Next hop: DEFAULT_INTERNET_GATEWAY\n ```\n\n Replace the following:\n - \u003cvar translate=\"no\"\u003eSHARED_VPC_NETWORK_NAME\u003c/var\u003e: The name of your Shared VPC network.\n - \u003cvar translate=\"no\"\u003eINSTANCE_TAGS\u003c/var\u003e: If you do not use any instance tags, do not specify anything in this field. If you do use instance tags, include `aef-instances` in your list of instance tags.\n - \u003cvar translate=\"no\"\u003eDEFAULT_INTERNET_GATEWAY\u003c/var\u003e: The default internet gateway.\n\n To learn more about compatible routes for Private Google Access, see\n the Private Google Access documentation on\n [routing options](/vpc/docs/configure-private-google-access#config-routing).\n2. Verify that you have a firewall rule that is compatible with\n Private Google Access. The firewall rule must be configured as\n follows.\n\n ```sh\n Network: SHARED_VPC_NETWORK_NAME\n Destination IP address range: 0.0.0.0/0\n Destination filter: IP ranges\n Direction of traffic: Egress\n Attach on match: Allow\n Instance tags: INSTANCE_TAGS\n ```\n\n Replace the following:\n - \u003cvar translate=\"no\"\u003eSHARED_VPC_NETWORK_NAME\u003c/var\u003e: The name of your Shared VPC network.\n - \u003cvar translate=\"no\"\u003eINSTANCE_TAGS\u003c/var\u003e: If you do not use any instance tags, do not specify anything in this field. If you do use instance tags, include `aef-instances` in your list of instance tags.\n\n To learn more about compatible firewall rules for\n Private Google Access, see the Private Google Access\n documentation on\n [firewall configuration](/vpc/docs/configure-private-google-access#config-firewall).\n\nConfigure your service to use only its internal IP address\n----------------------------------------------------------\n\n1. Update the Google Cloud CLI. This ensures that you are using a version of the\n gcloud CLI that supports private IP addresses for\n flexible environment apps.\n\n ```bash\n gcloud components update\n ```\n2. In your `app.yaml` file, add the `instance_ip_mode` field to the\n [`network` section](/appengine/docs/flexible/reference/app-yaml#network_settings)\n and set it to `internal`.\n\n - If your `app.yaml` file already has a `network` section, add the following\n line inside the `network` section:\n\n ```bash\n instance_ip_mode: internal\n ```\n\n \u003cbr /\u003e\n\n - If your `app.yaml` file doesn't have a `network` section, create the\n section and specify the instance IP mode by adding the following lines:\n\n ```bash\n network:\n instance_ip_mode: internal\n ```\n\n \u003cbr /\u003e\n\n Save these changes.\n3. Deploy the service.\n\n ```bash\n gcloud beta app deploy\n ```\n4. Verify configuration by checking the Instances page of the Google Cloud console.\n\n [Go to Instances](https://console.cloud.google.com/appengine/instances)\n\n Scroll down to the **Instances** table (below the **Summary** chart). In the\n **External IP** column, confirm that there is no IP address listed. The\n absence of an IP address in this column means that your instance has no\n external IP address. Even though this field is empty, your instance still has\n an internal IP address.\n\nSend external requests without an external IP address\n-----------------------------------------------------\n\nIf your service sends requests to the internet but you want to limit it to using\nonly its internal IP address, you can use [Cloud NAT](/nat/docs/overview) to\ncreate a gateway. Your service can send external requests through the\nCloud NAT gateway without using the default ephemeral external IP addresses.\n\n1. Follow the steps in the section\n [Configure your service to use only its internal IP address](#limit-to-internal).\n\n2. Follow the steps to\n [Configure Cloud NAT](/nat/docs/set-up-manage-network-address-translation).\n\nTo learn more about this approach, see the Cloud Architecture Center\ndocumentation on\n[Deploying Cloud NAT for fetching](/architecture/building-internet-connectivity-for-private-vms#deploying_cloud_nat_for_fetching)."]]
