[[["易于理解","easyToUnderstand","thumb-up"],["解决了我的问题","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["很难理解","hardToUnderstand","thumb-down"],["信息或示例代码不正确","incorrectInformationOrSampleCode","thumb-down"],["没有我需要的信息/示例","missingTheInformationSamplesINeed","thumb-down"],["翻译问题","translationIssue","thumb-down"],["其他","otherDown","thumb-down"]],["最后更新时间 (UTC)：2025-08-21。"],[[["\u003cp\u003eThe App Engine firewall controls incoming network traffic to your app, allowing or denying requests based on specified rules for IP ranges.\u003c/p\u003e\n"],["\u003cp\u003eBy default, the App Engine firewall allows all requests not matching a rule, but you can set the default to deny, blocking all unspecified traffic except for internal services, such as warmup requests, Cloud Scheduler, or Cloud Tasks.\u003c/p\u003e\n"],["\u003cp\u003eCertain types of traffic, such as warmup requests, Cloud Scheduler jobs, and Cloud Tasks, can bypass the firewall rules if the default rule is set to deny when using the standard environment.\u003c/p\u003e\n"],["\u003cp\u003eWhen using Cloud Load Balancing with App Engine, the load balancer does not interact with the App Engine firewall rules, so it's recommended to use ingress controls to restrict traffic directly to the load balancer.\u003c/p\u003e\n"],["\u003cp\u003eCached content can still be served publicly even after firewall rules are updated, so you should manage caching behaviors using headers like \u003ccode\u003eCache-Control\u003c/code\u003e and \u003ccode\u003eExpires\u003c/code\u003e to avoid security issues with the cached content.\u003c/p\u003e\n"]]],[],null,["# Understanding the App Engine firewall\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\n\nA **firewall** determines which network traffic is allowed to pass and which\ntraffic is rejected. Firewalls can apply to incoming traffic (ingress), outgoing\ntraffic (egress), or both. For App Engine, the App Engine firewall only\napplies to incoming traffic routed to your app or service.\n\nOverview\n--------\n\nThe App Engine firewall is checked for all types of\nrequests to your app, including:\n\n- Regular web traffic routed to the app's `appspot.com` address or custom domain.\n- Requests that arrive from [Cloud Load Balancing](/load-balancing).\n- Traffic from internal sources such as Compute Engine virtual machines (VMs) and Cloud Tasks.\n\nIn cases where your app is configured to use other networking services or\nproducts, you might need to create rules for controlling incoming traffic in\nboth the App Engine firewall and the firewall or security settings of other\nproducts. This guide covers the general behavior of the App Engine firewall,\nand details about those special use cases.\n\nApp Engine firewall rules\n-------------------------\n\nYou can [configure App Engine firewall rules](/appengine/docs/standard/creating-firewalls)\nusing the Google Cloud console, the Google Cloud CLI, or the Admin\nAPI by specifying rules that allow or block specified IP ranges.\n\nBy default, any request that does not match a rule is allowed access to your\napp. If you need to block all requests that do not match a specific rule\n(excluding requests from internal services allowed by default), change the\n`default` rule's action to `deny`.\n\n### Firewall feature\n\nIn the App Engine standard environment, the App Engine firewall can allow certain internal\ntraffic to bypass the firewall. This means that if you set the `default` rule to\n`deny`, requests from certain services destined for the App Engine standard environment do not\nget blocked. These are all types of traffic requested in the app's own\nconfiguration, or sent from the same app. Requests that bypass firewall rules in\nthis way include:\n\n- [Warmup requests](/appengine/docs/standard/configuring-warmup-requests)\n- Cloud Scheduler jobs using [App Engine HTTP](/scheduler/docs/creating#creating_jobs) (including [App Engine Cron](/appengine/docs/standard/scheduling-jobs-with-cron-yaml))\n- [App Engine tasks in Cloud Tasks](/tasks/docs/creating-appengine-tasks) (including App Engine Task Queues)\n\nFor apps that use the App Engine standard environment and services bundled with the [first\ngeneration runtimes](/appengine/docs/standard/runtimes), notifications from the\nlegacy Mail API also bypass the firewall.\n\nAllowing incoming requests from your services\n---------------------------------------------\n\nThe following table lists the IP ranges and App Engine firewall behavior for\ncommon services. The IP range you use depends on whether the incoming requests\nare delivered to a version that runs on the App Engine standard environment or\nflexible environment.\n\nDepending on your use case, these additional instructions might apply when\nconfiguring App Engine firewall rules:\n\n- Requests from newly created or updated App Engine Cron jobs sent to either the App Engine standard or flexible environment come from `0.1.0.2`. For Cron jobs created with older gcloud versions (earlier than 326.0.0), Cron requests will come from `0.1.0.1`. To learn more about how to identify requests from the App Engine Cron service, see [Validating cron requests](/appengine/docs/standard/scheduling-jobs-with-cron-yaml#validating_cron_requests).\n- If your app interacts with Cloud Load Balancing or is connected to a VPC network, see the [Interaction with other products or services](#interaction_with_other_products_or_services) section below.\n\n| **Caution:** Creating a rule for IP `0.0.0.0` will apply to **all** Compute Engine instances with Private Google Access enabled, not only the ones you own. Similarly, allowing requests from `0.1.0.40` will allow **any** App Engine app to make URL Fetch requests to your app.\n\n### App Engine standard example\n\nYour app running in the standard environment has two services: `frontend_service`\nand `backend_service`. `frontend_service` uses Cloud Tasks with\nApp Engine HTTP to send messages to `backend_service`. Since the `default`\nfirewall rule allows Cloud Tasks requests even if configured to `deny`, you do not need to create\na firewall rule for Cloud Tasks.\n\nHowever, if you wanted to restrict access to your app and explicitly block\nCloud Tasks requests, you would create a `deny` firewall rule for IP range `0.1.0.2/32`.\n\n### App Engine flexible example\n\nYour app running in the flexible environment has two services:\n`frontend_service` and `backend_service`, and has a firewall configured to deny\ntraffic by default. `frontend_service` uses Cloud Tasks with\nApp Engine HTTP to send messages to `backend_service`. Since the `default`\nfirewall rule denies Cloud Tasks requests, you would need to create an\n`allow` firewall rule for `0.1.0.2/32`.\n\nInteraction with other products or services\n-------------------------------------------\n\n### Cloud Load Balancing\n\nIf you use [Cloud Load Balancing and serverless NEGs](/load-balancing/docs/negs/serverless-neg-concepts), note the following:\n\n- The load balancer does not interfere or interact with App Engine firewall rules. The App Engine firewall rules are not evaluated until a serverless NEG directs traffic to App Engine.\n\n\u003c!-- --\u003e\n\n- We recommend that you [use ingress controls](/appengine/docs/standard/application-security#ingress_controls)\n so that your app only receives requests sent from the load balancer\n (and the VPC if you use it). Otherwise, users can use your app's\n App Engine URL to bypass the load balancer, Cloud Armor\n security policies, SSL certificates, and private keys that are passed through\n the load balancer.\n\n- If your [ingress controls](/appengine/docs/standard/application-security#ingress_controls) are set to receive `internal-and-cloud-load-balancing` traffic, leave the default App Engine firewall rule as is (`allow`), and use [Google Cloud Armor web application firewall (WAF) rules](/armor/docs/rule-tuning).\n\nPreventing access to cached content\n-----------------------------------\n\nThe App Engine firewall sits behind mechanisms that cache content, for example\nweb proxies and browsers. When content is cached, that content is served\npublicly from the specific URL until it expires and can be accessed even after\ncreating new firewall rules.\nFor information about changing the default expiration time for static content or preventing static content from being cached, see [Cache expiration](/appengine/docs/standard/how-requests-are-handled#static_cache_expiration).\n\n\u003cbr /\u003e\n\nTo prevent dynamic content output from your app's code from being cached, use\nthe `Cache-Control` and `Expires` HTTP response headers. For more information about\nthese HTTP headers, including how to control caching, see\n[Avoiding caching](https://wikipedia.org/wiki/List_of_HTTP_header_fields#Avoiding_caching).\n\n\nWhat's next\n-----------\n\nFollow the instructions in\n[Creating Firewalls](/appengine/docs/standard/creating-firewalls) to\nlearn how to configure App Engine firewall rules."]]
