如果两个或更多基于政策的路由具有相同的优先级，并且数据包的特征与至少两个此类基于政策的路由匹配，则 Google Cloud会使用内部算法来选择单个基于政策的路由。所选基于政策的路由可能不是数据包特征的最具体匹配项，因为基于政策的路由不使用最长前缀匹配。确保同一 VPC 网络中的所有基于政策的路由都具有唯一的优先级。
您可以使用 Google Cloud CLI 或发送 API 请求来创建基于政策的路由，该路由会跳过其他基于政策的路由。对于 gcloud CLI，请使用 --next-hop-other-routes=DEFAULT_ROUTING 标志。对于 API 请求，请在请求正文中添加 "nextHopOtherRoutes": "DEFAULT_ROUTING"。
如果此类基于政策的路由与数据包的特征匹配，且优先级高于其他基于政策的路由，则 Google Cloud会忽略其他基于政策的路由，并继续进行 VPC 路由顺序中最具体的目标这一步骤。
[[["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)：2025-09-05。"],[],[],null,["# Policy-based routes\n===================\n\nThis document provides an overview of Policy-based Routing.\n\nPolicy-based routes let you select a next hop based on more than a packet's\ndestination IP address. You can match traffic by protocol and source IP address\nas well. Matching traffic is redirected to an internal passthrough Network Load Balancer. This can help\nyou insert appliances such as firewalls into the path of network traffic.\n\nSpecifications\n--------------\n\n- When you [create a policy-based\n route](/vpc/docs/use-policy-based-routes#create), you select which resources the policy-based route applies to. The route can apply to:\n - All VM instances, Cloud Interconnect VLAN attachments, and Cloud VPN tunnels that are in the same VPC network as the route\n - Only VM instances that are in the same VPC network as the route and identified by [network\n tags](/vpc/docs/add-remove-network-tags)\n - Only VLAN attachments that are in a specific region of the same VPC network as the route. You can't create a policy-based route that only applies to a single VLAN attachment or Cloud VPN tunnel\n- The next hop of a policy-based route must be a valid [internal passthrough Network Load Balancer](/load-balancing/docs/internal). This internal passthrough Network Load Balancer must either be in the same VPC network as the policy-based route or in a VPC network that is connected to the route's VPC network through [VPC Network Peering](/vpc/docs/vpc-peering).\n- The backend VM instances of the next hop internal passthrough Network Load Balancer must have [IP\n forwarding](/vpc/docs/using-routes#create-vm-canipforward) enabled.\n- Policy-based routes are evaluated before subnet routes, static routes, and dynamic routes, but after [special routing\n paths](/vpc/docs/routes#special_return_paths). For more information, see the [Policy-based routes](/vpc/docs/routes#check-for-pbrs) step in the routing order.\n- If two or more policy-based routes have the same priority, and a packet's characteristics match at least two of those policy-based routes, Google Cloud selects a single policy-based route by using an internal algorithm. The selected policy-based route might not be the most specific match for the packet's characteristics because policy-based routes don't use longest-prefix matching. Make sure that all policy-based routes in the same VPC network have unique priorities.\n- A policy-based route can apply to either IPv4 or IPv6 traffic.\n- You can create a single rule for one-way traffic or multiple rules to handle bidirectional traffic.\n\nLimitations\n-----------\n\n- Policy-based routes are not exchanged between VPC networks that are connected through [VPC Network Peering](/vpc/docs/vpc-peering).\n- Policy-based routes are not exchanged between [Network Connectivity Center spokes and hubs](/network-connectivity/docs/network-connectivity-center/concepts/vpc-spokes-overview).\n- Policy-based routes don't support matching traffic based on port.\n- It is not possible to update a policy-based route after it is created. If you want to update a route, [delete the route](/vpc/docs/use-policy-based-routes#delete) and then create a new one.\n- The internal passthrough Network Load Balancer forwarding rule must have a dedicated IP address that's not used by any other internal passthrough Network Load Balancer. Using a shared IP address (IP address purpose set to `SHARED_LOADBALANCER_VIP`) is not supported.\n- Policy-based routes can interfere with communication between the GKE control plane and nodes. For more information, see [Use policy-based routes with GKE](/vpc/docs/use-policy-based-routes#pbr-with-gke).\n- Policy-based routes can't route packets to Private Service Connect endpoints or backends.\n - For information about using policy-based routes in VPC networks with endpoints or backends that access published services, see [Policy-based routes and Private Service Connect for published services](/vpc/docs/use-policy-based-routes#pbr-with-psc).\n - For information about using policy-based routes in VPC networks with endpoints or backends that access Google APIs and services, see [Policy-based routes and accessing Google APIs and services](/vpc/docs/use-policy-based-routes#pbr-with-pga-psc-apis).\n- Only VLAN attachments that use [Dataplane v2](/network-connectivity/docs/interconnect/concepts/terminology#dataplaneVersion) can use policy-based routes. To inspect your VLAN attachment to check what version it uses, see the instructions for [Dedicated Interconnect](/network-connectivity/docs/interconnect/how-to/dedicated/viewing-vlans#dataplane) or [Partner Interconnect](/network-connectivity/docs/interconnect/how-to/partner/viewing-vlans#dataplane).\n\nSkipping other policy-based routes\n----------------------------------\n\nYou can create a policy-based route that skips other policy-based\nroutes by using the Google Cloud CLI or sending an API request. For the\ngcloud CLI, use the\n`--next-hop-other-routes=DEFAULT_ROUTING` flag. For an API request,\ninclude `\"nextHopOtherRoutes\": \"DEFAULT_ROUTING\"` with the request body.\n\nIf a policy-based\nroute of this type matches a packet's characteristics and has\na higher priority than other matching policy-based routes, Google Cloud\nignores the other policy-based routes and proceeds to the *most specific\ndestination* step of the\n[VPC routing order](/vpc/docs/routes#routeselection).\n\nFor example, consider a policy-based route that uses a next hop\ninternal passthrough Network Load Balancer. This policy-based route has a source\nrange of `0.0.0.0/0` and a network tag of `compute-vm`.\n\nTo skip evaluation of the first policy-based route when packet sources match\na specific IP address range, create a higher-priority policy-based route that\nis configured to skip other policy-based routes. Set the source IP\naddress range for this higher-priority policy-based route to the\nsource IP address range of the systems that need to skip policy-based routing.\n\nQuota\n-----\n\nThere is a limit for how many policy-based routes you can create in a single\nproject. For more information, see the per-project [quotas](/vpc/docs/quota#policy-based-routes-quota)\nin the VPC documentation."]]
