接下來，IAP 會檢查使用者的瀏覽器憑證。如果不存在任何憑證，系統會將使用者重新導向至 OAuth 2.0 Google 帳戶登入流程，以將憑證儲存在瀏覽器 Cookie 中，供未來登入使用。如果您需要為現有使用者建立 Google 帳戶，可以使用 Google Cloud Directory Sync 同步處理 Active Directory 或 LDAP 伺服器。
如果要求憑證有效，驗證伺服器會使用這些憑證取得使用者的身分識別資訊 (電子郵件地址與使用者 ID)；然後使用身分識別資訊檢查使用者的 IAM 角色，並查看使用者是否已獲授權，可以存取資源。
如果您使用 Compute Engine 或 Google Kubernetes Engine，能夠存取虛擬機器 (VM) 應用程式提供通訊埠的使用者可以略過 IAP 驗證。如果執行程式碼的 VM 與受 IAP 保護的應用程式所在的 VM 相同，Compute Engine 與 GKE 防火牆無法避免其進行存取。防火牆規則若正確設定，即能夠保護來自另一個 VM 的存取。請瞭解您的責任以確保安全性。
[[["容易理解","easyToUnderstand","thumb-up"],["確實解決了我的問題","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["難以理解","hardToUnderstand","thumb-down"],["資訊或程式碼範例有誤","incorrectInformationOrSampleCode","thumb-down"],["缺少我需要的資訊/範例","missingTheInformationSamplesINeed","thumb-down"],["翻譯問題","translationIssue","thumb-down"],["其他","otherDown","thumb-down"]],["上次更新時間：2025-08-18 (世界標準時間)。"],[[["\u003cp\u003eIdentity-Aware Proxy (IAP) is a Google Cloud service that establishes a centralized authorization layer for HTTPS applications, enabling application-level access control instead of relying on network firewalls.\u003c/p\u003e\n"],["\u003cp\u003eIAP enforces access control policies for applications and resources by authenticating users and verifying their Identity and Access Management (IAM) roles before allowing access, utilizing signed headers or the App Engine Users API for securing applications.\u003c/p\u003e\n"],["\u003cp\u003eWhen enabled, IAP performs authentication and authorization checks on user requests, first by checking user credentials and then the user's IAM role, automatically creating OAuth 2.0 client credentials for this purpose.\u003c/p\u003e\n"],["\u003cp\u003eIAP allows for context-aware access, extending secure access to Google Cloud console, APIs, virtual machines, and web applications, providing enhanced control over resource access.\u003c/p\u003e\n"],["\u003cp\u003eWhile IAP manages external access, users must configure firewalls, load balancers, or Cloud Run ingress controls to prevent internal traffic within the project from bypassing IAP authentication, and to use signed headers or the App Engine Users API.\u003c/p\u003e\n"]]],[],null,["# Identity-Aware Proxy overview\n\nThis page describes the basic concepts of Identity-Aware Proxy\n(IAP), a Google Cloud global service.\n\nIAP lets you establish a central authorization\nlayer for applications accessed by HTTPS, so you can use an application-level\naccess control model instead of relying on network-level firewalls.\n\nIAP policies scale across your organization. You can define\naccess policies centrally and apply them to all of your applications and\nresources. When you assign a dedicated team to create and enforce policies, you\nprotect your project from incorrect policy definition or implementation in any\napplication.\n\nWhen to use IAP\n---------------\n\nUse IAP when you want to enforce access control policies\nfor applications and resources. IAP works with\n[signed headers](/iap/docs/signed-headers-howto) or the App Engine\nstandard environment [Users API](/appengine/docs/standard/services/users)\nto secure your app. With IAP, you can set up group-based\napplication access: a resource could be accessible for employees and\ninaccessible for contractors, or only accessible to a specific department.\n\nHow IAP works\n-------------\n\nWhen an application or resource is protected by IAP, it can\nonly be accessed through the proxy by\n[principals](/iam/docs/overview#concepts_related_identity), also known as users,\nwho have the correct\n[Identity and Access Management (IAM) role](/iam/docs/understanding-roles).\nWhen you grant a user access to an application or resource by\nIAP, they're subject to the fine-grained access controls\nimplemented by the product in use without requiring a VPN. When a user tries\nto access an IAP-secured resource, IAP\nperforms authentication and authorization checks.\nApp Engine Cloud Run Compute Engine GKE On-premises\n\n### Authentication\n\nRequests to your Google Cloud resources come through Cloud Run,\nApp Engine, and Cloud Load Balancing (External and Internal HTTP(S)\nLoad Balancing). The serving infrastructure code for these products checks if\nIAP is enabled for the app or backend service. If\nIAP is enabled, information about the protected resource is\nsent to the IAP authentication server. This includes\ninformation like the Google Cloud project number, the request URL, and any\nIAP credentials in the request headers or cookies.\n\nNext, IAP checks the user's browser credentials. If none\nexist, the user is redirected to an OAuth 2.0 Google Account sign-in flow that\nstores a token in a browser cookie for future sign-ins. If you need to create\nGoogle Accounts for your existing users, you can use\n[Google Cloud Directory Sync](https://support.google.com/a/answer/106368)\nto synchronize with your Active Directory or LDAP server.\n\nIf the request credentials are valid, the authentication server uses those\ncredentials to get the user's identity (email address and user ID). The\nauthentication server then uses the identity to check the user's\nIAM role and check if the user is authorized to access the\nresource.\n\nIf you're using Compute Engine or Google Kubernetes Engine,\nusers who can access the application-serving port of the Virtual Machine (VM)\ncan bypass IAP authentication. Compute Engine and GKE\nfirewall rules can't protect against access from code running on the same VM as\nthe IAP-secured application. Firewall rules can protect\nagainst access from another VM, but only if properly configured. Learn\nabout [your responsibilities](#your_responsibilities) to ensure security.\n\nIf you're using Cloud Run, you can [enable\nIAP](/run/docs/securing/identity-aware-proxy-cloud-run) in the\nfollowing ways:\n\n- Directly on your Cloud Run services. This enables IAP to protect all ingress paths to Cloud Run, including the [auto-assigned URL](/run/docs/triggering/https-request) and any configured load balancer URL. This configuration is useful when you have a single Cloud Run service to enable IAP for.\n- Through a load balancer with a Cloud Run backend. This configuration is useful when you have multiple Cloud Run services in different regions behind a single global load balancer. In this configuration, the auto-assigned URL is unprotected by IAP and might be directly accessible. Learn more about [your\n responsibilities](#your_responsibilities) to ensure security.\n\nIf a Cloud Run service is behind a load balancer, don't enable\nIAP on both the load balancer and the Cloud Run\nservice.\n\n### Authorization\n\nAfter authentication, IAP applies the relevant\nIAM policy to check if the user is authorized to access the\nrequested resource. If the user has the **IAP-secured Web App User** role on the\nGoogle Cloud console project where the resource exists, they're authorized to\naccess the application. To manage the **IAP-secured Web App User** role list,\nuse the\n[IAP panel on the Google Cloud console](https://console.cloud.google.com/security/iap/).\n\nWhen you turn on IAP for a resource, it automatically\ncreates an OAuth 2.0 client ID and secret. If you delete the automatically\ngenerated OAuth 2.0 credentials, IAP won't function\ncorrectly. You can view and manage OAuth 2.0 credentials in the\n[Google Cloud console APIs \\& services](https://console.cloud.google.com/apis/dashboard).\n\n#### Context-aware access\n\nAs part of the [authorization](#iap-auth) step, you can use context-aware access to provide\nsecure access to the following types of resources:\n\n##### Google Cloud console and APIs\n\n- First layer of defense in protecting infrastructure access to Google Cloud.\n- Advanced context-aware Google Cloud access to users.\n\n##### Virtual Machines (VMs)\n\n- Enables administrative SSH/RDP access to VMs in Google Cloud and in other clouds.\n- Lets you implement robust context-aware controls to restrict access to only designated administrators.\n\n##### Web applications\n\n- Provides authorization and authentication for web applications hosted in Google Cloud and other clouds.\n- Provides continuous authorization to prevent unauthorized access and data loss.\n\nYour responsibilities\n---------------------\n\nIAP secures authentication and authorization of all requests\nto Cloud Run, App Engine, Cloud Load Balancing (HTTPS),\nand internal HTTP load balancing.\n\nTo ensure security, you must take the following precautions:\n\n- If you're enabling IAP on a load balancer, verify whether the backend resources can be accessed directly.\n - If the backend resource is a VM, configure your firewall rules to protect against traffic that doesn't come through the load balancer. IAP doesn't protect against activity within a project, such as another VM inside the project.\n - If the backend resource is a Cloud Run service, you can disable the run.app URL to ensure that all ingress comes in through the load balancer. If you choose to leave the run.app URL enabled, you should use [ingress controls](/run/docs/securing/ingress) to block traffic from outside your network.\n- Update your app to use [signed headers](/iap/docs/signed-headers-howto) or use the App Engine standard environment [Users API](/appengine/docs/standard/services/users).\n\nWhat's next\n-----------\n\n- Get started with IAP by completing one of the following tasks:\n - Enable IAP [directly on your\n Cloud Run](/run/docs/securing/identity-aware-proxy-cloud-run) services or on a [load balancer with a\n Cloud Run backend](/iap/docs/enabling-cloud-run).\n - Complete the App Engine quickstart to [Manage Access with Google\n Accounts](/iap/docs/app-engine-quickstart).\n - Enable [IAP for Compute Engine](/iap/docs/enabling-compute-howto).\n - Enable [IAP for GKE](/iap/docs/enabling-kubernetes-howto).\n - Enable [IAP for on-premises apps](/iap/docs/enabling-on-prem-howto).\n- Learn more:\n - [Authenticating to Compute Engine](/compute/docs/authentication)\n - [App Engine user authentication options](/appengine/docs/python/oauth)\n - [Using OAuth 2.0 to access Google APIs](https://developers.google.com/identity/protocols/OAuth2)\n - [Google Cloud auth guide](/docs/authentication)\n - [Setting up a load balancer](/iap/docs/load-balancer-howto)\n - [Setting up a load balancer with Cloud Run (fully managed)](/load-balancing/docs/https/setting-up-https-serverless)\n - [Restricting ingress for Cloud Run](/run/docs/securing/ingress)"]]
