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Cloud DNS uses the following procedure to answer queries from
Compute Engine virtual machine (VM) instances and
Google Kubernetes Engine (GKE) nodes.
For Compute Engine VMs other than GKE nodes,
Cloud DNS follows the VPC network resolution
order to process queries it receives. Each VM must be configured to
use the metadata server IP address (169.254.169.254) as its name server.
Cluster-scoped response policies and private zones
Match using rules in GKE cluster-scoped response
policies. Cloud DNS scans all applicable GKE
cluster-scoped response policies for a rule where the DNS name attribute
matches as much of the query as possible. Cloud DNS uses
longest-suffix matching to scan cluster-scoped response policies.
If Cloud DNS finds a matching response policy rule and the
rule serves local data, then Cloud DNS returns the local
data as its response, completing the name resolution process.
If Cloud DNS finds a matching response policy rule and the
rule's behavior bypasses the response policy, then Cloud DNS
continues to the next step.
If Cloud DNS fails to find a matching response policy or if
there isn't an applicable cluster-scoped response policy for the node,
then Cloud DNS continues to the next step.
Match records in cluster-scoped private zones. Cloud DNS scans
all cluster-scoped managed private zones for a record that matches as much of
the query as possible. Cloud DNS uses longest-suffix matching to
find records in cluster-scoped private zones.
If the most specific match for the query is the zone name of a
cluster-scoped private zone, Cloud DNS uses that zone's record
data to resolve the request.
If the zone contains a record that exactly matches the query, Cloud DNS
returns that record's data.
If the zone doesn't contain a matching record, Cloud DNS returns
NXDOMAIN.
If the most specific match for the query is the zone name of a
cluster-scoped forwarding zone, then Cloud DNS forwards the
query to one of the forwarding zone's forwarding targets to complete the
name resolution process. Cloud DNS returns one of the following
responses.
The response received from the forwarding target.
A SERVFAIL response, if the forwarding target doesn't respond to
Cloud DNS.
If the query doesn't match any cluster-scoped private zone,
Cloud DNS continues to the VPC network
resolution order.
VPC network resolution order
Match using VPC network alternative name server. If the
VPC network has an outbound server
policy,
Google Cloud forwards the query to one of the alternative name
servers defined in that
policy to complete the name resolution process.
If two or more alternative name servers exist in the outbound server
policy, Cloud DNS ranks the alternative name servers using an
internal algorithm. Beginning with equal ranks, alternative name servers
increase in rank based on higher rates of successful responses (including
NXDOMAIN responses) and based on the shortest round-trip time (the lowest
response latency).
Cloud DNS sends queries to alternative name servers and returns
responses using the following process.
If two or more alternative name servers exist in the outbound server
policy, Cloud DNS first sends the query to the highest-ranked
alternative name server, then to the next-ranked alternative name
server if Cloud DNS does not receive any response from the
highest-ranked alternative name server. If Cloud DNS doesn't
receive any response from the next-ranked alternative name server,
Cloud DNS continues to query alternative name servers by
descending rank until it exhausts the list of alternative name servers.
If Cloud DNS receives a response from an alternative name
server, Cloud DNS returns that response. Responses include
NXDOMAIN responses.
If Cloud DNS does not receive a response from all
alternative name servers in the outbound server policy,
Cloud DNS synthesizes a SERVFAIL response. To troubleshoot
alternative name server connectivity, see Alternative name server
network requirements.
If the VPC network does not have an outbound server policy,
Cloud DNS continues to the next step.
Match using rules in VPC network-scoped response
policies. Cloud DNS scans all applicable VPC
network response policies for a rule where the DNS name attribute matches
as much of the query as possible. Cloud DNS uses longest-suffix
matching to scan VPC network-scoped response policies.
If Cloud DNS finds a matching response policy rule and the
rule serves local data, then Cloud DNS returns the local data
as its response, completing the name resolution process.
If Cloud DNS finds a matching response policy rule and the
rule's behavior bypasses the response policy, then Cloud DNS
continues to the next step.
If Cloud DNS fails to find a matching response policy or if
there isn't an applicable VPC network-scoped response
policy for the VM or node, then Cloud DNS continues to the next
step.
Match records in VPC network-scoped managed private zones.
Cloud DNS scans all managed private zones authorized for the
VPC network for a record that matches as much of the query as
possible. Cloud DNS uses longest-suffix matching to find records.
If the most specific match for the query is the zone name of a
VPC network-scoped private zone, Cloud DNS uses that
zone's record data to resolve the request.
If the zone contains a record that exactly matches the query, Cloud DNS
returns the record's data.
If the zone doesn't contain a matching record, Cloud DNS returns
NXDOMAIN.
If the most specific match for the query is the zone name of a
VPC network-scoped forwarding zone, then Cloud DNS
forwards the query to one of the forwarding zone's forwarding targets to
complete the name resolution process. Cloud DNS returns one of
the following responses.
The response received from the forwarding target.
A SERVFAIL response, if the forwarding target doesn't respond to
Cloud DNS.
If the most specific match for the query is the name of a VPC
network-scoped peering zone, Cloud DNS stops the current name
resolution process and begins a new name resolution process from the
perspective of the peering zone's target VPC network.
If the query doesn't match a private zone, forwarding zone, or peering zone,
Cloud DNS continues to the next step.
Match records in Compute Engine internal zones.
Cloud DNS scans all applicable Compute Engine
internal DNS zones for a record that matches as
much of the query as possible. Cloud DNS uses longest-suffix
matching to find records.
If the most specific match for the query is a Compute Engine
internal DNS name, Cloud DNS returns the internal IP address of the
VM's network interface or its reverse lookup pointer as its response,
completing the name resolution process.
Match record using public DNS query. Google Cloud follows the
start of authority (SOA) record to query publicly available zones, including
Cloud DNS public zones. Cloud DNS returns one of the
following responses.
The response received from an authoritative name server.
An NXDOMAIN response, if the record doesn't exist.
Example
Suppose that you have two VPC networks, vpc-a and vpc-b, and
a GKE cluster, cluster-a, along with the following scoped
resources:
vpc-a is authorized to query the following private zones. Note the trailing
dot in each entry:
static.example.com.
10.internal.
peer.com. is a peering zone that can query the VPC
name resolution order of vpc-b.
vpc-a is not associated with any outbound server or response policies.
cluster-a is authorized to query a private zone called example.com.
cluster-a is also not associated with any outbound server or response
policies.
A VM in cluster-a can query:
example.com and children (including static.example.com),
answered by the private zone called example.com, authorized to
cluster-a.
10.internal on vpc-a.
peer.com by using the peering zone.
A VM that is not in cluster-a can query:
static.example.com and children, answered by the private zone called
static.example.com authorized to vpc-a. Queries for example.com
return internet responses.
10.internal on vpc-a.
peer.com by using the peering zone.
What's next
To find solutions for common issues that you might encounter when using
Cloud DNS, see Troubleshooting.
[[["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 2025-08-25 UTC."],[[["\u003cp\u003eCloud DNS handles queries from Compute Engine VMs by following the VPC network resolution order, with each VM needing to use the metadata server IP address (169.254.169.254) as its name server.\u003c/p\u003e\n"],["\u003cp\u003eFor GKE nodes, Cloud DNS first attempts to match queries using cluster-scoped response policies and private zones before proceeding to the VPC network resolution order.\u003c/p\u003e\n"],["\u003cp\u003eThe VPC network resolution order involves matching queries against alternative name servers, VPC network-scoped response policies, managed private zones, Compute Engine internal zones, and finally, public DNS queries.\u003c/p\u003e\n"],["\u003cp\u003eLongest-suffix matching is utilized by Cloud DNS to scan cluster-scoped and VPC network-scoped resources for records or rules that match queries.\u003c/p\u003e\n"],["\u003cp\u003eOutbound server policies help reroute queries through alternative name servers, which are ranked based on response success rates and latency, for a faster resolution.\u003c/p\u003e\n"]]],[],null,["# Name resolution order\n\nCloud DNS uses the following procedure to answer queries from\nCompute Engine virtual machine (VM) instances and\nGoogle Kubernetes Engine (GKE) nodes.\n\nFor Compute Engine VMs other than GKE nodes,\nCloud DNS follows the [VPC network resolution\norder](#vpc_steps) to process queries it receives. Each VM must be configured to\nuse the metadata server IP address (`169.254.169.254`) as its name server.\n\nFor GKE nodes:\n\n1. Cloud DNS first attempts to match a query using [cluster-scoped\n response policies and private zones](#gke_steps).\n\n2. Cloud DNS continues by following the [VPC network\n resolution order](#vpc_steps).\n\nCluster-scoped response policies and private zones\n--------------------------------------------------\n\n1. **Match using rules in GKE cluster-scoped response\n policies**. Cloud DNS scans all applicable GKE\n cluster-scoped response policies for a rule where the DNS name attribute\n matches as much of the query as possible. Cloud DNS uses\n longest-suffix matching to scan cluster-scoped response policies.\n\n 1. If Cloud DNS finds a matching response policy rule *and* the\n rule serves local data, then Cloud DNS returns the local\n data as its response, completing the name resolution process.\n\n 2. If Cloud DNS finds a matching response policy rule *and* the\n rule's behavior bypasses the response policy, then Cloud DNS\n continues to the next step.\n\n 3. If Cloud DNS fails to find a matching response policy *or* if\n there isn't an applicable cluster-scoped response policy for the node,\n then Cloud DNS continues to the next step.\n\n2. **Match records in cluster-scoped private zones**. Cloud DNS scans\n all cluster-scoped managed private zones for a record that matches as much of\n the query as possible. Cloud DNS uses longest-suffix matching to\n find records in cluster-scoped private zones.\n\n 1. If the most specific match for the query is the zone name of a\n cluster-scoped private zone, Cloud DNS uses that zone's record\n data to resolve the request.\n\n - If the zone contains a record that exactly matches the query, Cloud DNS returns that record's data.\n - If the zone doesn't contain a matching record, Cloud DNS returns `NXDOMAIN`.\n 2. If the most specific match for the query is the zone name of a\n cluster-scoped forwarding zone, then Cloud DNS forwards the\n query to one of the forwarding zone's forwarding targets to complete the\n name resolution process. Cloud DNS returns one of the following\n responses.\n\n - The response received from the forwarding target.\n - A `SERVFAIL` response, if the forwarding target doesn't respond to Cloud DNS.\n 3. If the query doesn't match any cluster-scoped private zone,\n Cloud DNS continues to the [VPC network\n resolution order](#vpc_steps).\n\nVPC network resolution order\n----------------------------\n\n1. **Match using VPC network alternative name server** . If the\n VPC network has an [outbound server\n policy](/dns/docs/server-policies-overview#dns-server-policy-out),\n Google Cloud forwards the query to one of the [alternative name\n servers](/dns/docs/server-policies-overview#altns-targets) defined in that\n policy to complete the name resolution process.\n\n If two or more alternative name servers exist in the outbound server\n policy, Cloud DNS ranks the alternative name servers using an\n internal algorithm. Beginning with equal ranks, alternative name servers\n increase in rank based on higher rates of successful responses (including\n `NXDOMAIN` responses) *and* based on the shortest round-trip time (the lowest\n response latency).\n\n Cloud DNS sends queries to alternative name servers and returns\n responses using the following process.\n - If two or more alternative name servers exist in the outbound server\n policy, Cloud DNS first sends the query to the highest-ranked\n alternative name server, then to the next-ranked alternative name\n server if Cloud DNS does *not* receive *any* response from the\n highest-ranked alternative name server. If Cloud DNS doesn't\n receive any response from the next-ranked alternative name server,\n Cloud DNS continues to query alternative name servers by\n descending rank until it exhausts the list of alternative name servers.\n\n - If Cloud DNS receives a response from an alternative name\n server, Cloud DNS returns that response. Responses include\n `NXDOMAIN` responses.\n\n - If Cloud DNS does *not* receive a response from *all*\n alternative name servers in the outbound server policy,\n Cloud DNS synthesizes a `SERVFAIL` response. To troubleshoot\n alternative name server connectivity, see [Alternative name server\n network requirements](/dns/docs/server-policies-overview#altns-net-req).\n\n If the VPC network does *not* have an outbound server policy,\n Cloud DNS continues to the next step.\n2. **Match using rules in VPC network-scoped response\n policies**. Cloud DNS scans all applicable VPC\n network response policies for a rule where the DNS name attribute matches\n as much of the query as possible. Cloud DNS uses longest-suffix\n matching to scan VPC network-scoped response policies.\n\n 1. If Cloud DNS finds a matching response policy rule *and* the\n rule serves local data, then Cloud DNS returns the local data\n as its response, completing the name resolution process.\n\n 2. If Cloud DNS finds a matching response policy rule *and* the\n rule's behavior bypasses the response policy, then Cloud DNS\n continues to the next step.\n\n 3. If Cloud DNS fails to find a matching response policy *or* if\n there isn't an applicable VPC network-scoped response\n policy for the VM or node, then Cloud DNS continues to the next\n step.\n\n3. **Match records in VPC network-scoped managed private zones**.\n Cloud DNS scans all managed private zones authorized for the\n VPC network for a record that matches as much of the query as\n possible. Cloud DNS uses longest-suffix matching to find records.\n\n 1. If the most specific match for the query is the zone name of a\n VPC network-scoped private zone, Cloud DNS uses that\n zone's record data to resolve the request.\n\n - If the zone contains a record that exactly matches the query, Cloud DNS returns the record's data.\n - If the zone doesn't contain a matching record, Cloud DNS returns `NXDOMAIN`.\n 2. If the most specific match for the query is the zone name of a\n VPC network-scoped forwarding zone, then Cloud DNS\n forwards the query to one of the forwarding zone's forwarding targets to\n complete the name resolution process. Cloud DNS returns one of\n the following responses.\n\n - The response received from the forwarding target.\n - A `SERVFAIL` response, if the forwarding target doesn't respond to Cloud DNS.\n 3. If the most specific match for the query is the name of a VPC\n network-scoped peering zone, Cloud DNS stops the current name\n resolution process and begins a new name resolution process from the\n perspective of the peering zone's target VPC network.\n\n If the query doesn't match a private zone, forwarding zone, or peering zone,\n Cloud DNS continues to the next step.\n4. **Match records in Compute Engine internal zones** .\n Cloud DNS scans all applicable [Compute Engine\n internal DNS zones](/compute/docs/internal-dns) for a record that matches as\n much of the query as possible. Cloud DNS uses longest-suffix\n matching to find records.\n\n 1. If the most specific match for the query is a Compute Engine internal DNS name, Cloud DNS returns the internal IP address of the VM's network interface or its reverse lookup pointer as its response, completing the name resolution process.\n5. **Match record using public DNS query**. Google Cloud follows the\n start of authority (SOA) record to query publicly available zones, including\n Cloud DNS public zones. Cloud DNS returns one of the\n following responses.\n\n - The response received from an authoritative name server.\n - An `NXDOMAIN` response, if the record doesn't exist.\n\nExample\n-------\n\nSuppose that you have two VPC networks, `vpc-a` and `vpc-b`, and\na GKE cluster, `cluster-a`, along with the following scoped\nresources:\n\n1. `vpc-a` is authorized to query the following private zones. Note the trailing\n dot in each entry:\n\n - `static.example.com.`\n - `10.internal.`\n2. `peer.com.` is a peering zone that can query the VPC\n name resolution order of `vpc-b`.\n\n3. `vpc-a` is not associated with any outbound server or response policies.\n\n4. `cluster-a` is authorized to query a private zone called `example.com`.\n `cluster-a` is also not associated with any outbound server or response\n policies.\n\n5. A VM in `cluster-a` can query:\n\n - `example.com` and children (including `static.example.com`), answered by the private zone called `example.com`, authorized to `cluster-a`.\n - `10.internal` on `vpc-a`.\n - `peer.com` by using the peering zone.\n6. A VM that is *not* in `cluster-a` can query:\n\n - `static.example.com` and children, answered by the private zone called `static.example.com` authorized to `vpc-a`. Queries for `example.com` return internet responses.\n - `10.internal` on `vpc-a`.\n - `peer.com` by using the peering zone.\n\nWhat's next\n-----------\n\n- To find solutions for common issues that you might encounter when using Cloud DNS, see [Troubleshooting](/dns/docs/troubleshooting).\n- To get an overview of Cloud DNS, see [Cloud DNS overview](/dns/docs/overview).\n- To learn how to configure response policies, see [Manage response policies\n and rules](/dns/docs/zones/manage-response-policies)."]]
