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Question 16
A company needs to connect their on-premises data center to Google Cloud with a dedicated, low-latency connection. Which service should they use?
A) Cloud VPN
B) Cloud Interconnect
C) Cloud Router
D) VPC Peering
Answer: B
Explanation:
Cloud Interconnect provides dedicated, low-latency physical connections between on-premises networks and Google Cloud, offering higher bandwidth and more predictable performance than internet-based connections. This service is ideal for enterprises requiring consistent, high-throughput connectivity for hybrid cloud architectures, large-scale data transfers, or latency-sensitive applications. Cloud Interconnect comes in two types: Dedicated Interconnect providing direct physical connections to Google’s network, and Partner Interconnect offering connections through supported service providers.
Dedicated Interconnect provides 10 Gbps or 100 Gbps circuits directly connecting customer networks to Google’s network at supported colocation facilities. Organizations provision physical cross-connects between their equipment and Google’s infrastructure in these facilities. This option delivers the highest performance and lowest latency but requires physical presence in supported locations. Multiple Interconnect connections can be provisioned for redundancy and additional bandwidth.
Partner Interconnect enables connectivity through supported service providers for organizations without access to colocation facilities or requiring lower bandwidth than Dedicated Interconnect minimums. Service providers offer connections ranging from 50 Mbps to 10 Gbps, providing flexibility for various bandwidth requirements. Partner Interconnect extends Google Cloud connectivity to more locations through provider networks.
VLAN attachments or interconnectAttachments configure logical connections over physical Interconnect circuits. Each VLAN attachment connects to a specific VPC network and Cloud Router, enabling dynamic route exchange via BGP. Multiple VLAN attachments can share physical Interconnect circuits, allowing multiple VPC networks or regions to use the same physical connection efficiently.
Cloud Routers work with Cloud Interconnect to dynamically exchange routes between on-premises networks and Google Cloud using BGP. This dynamic routing eliminates manual route management and enables automatic failover between redundant connections. Cloud Routers advertise VPC subnets to on-premises networks and learn on-premises routes, maintaining up-to-date routing information.
Redundancy configurations for Cloud Interconnect follow best practices for high availability. Recommended topologies include dual Interconnect connections in different edge availability domains, redundant Cloud Routers in each region, and redundant on-premises routers. This redundancy protects against connection failures, equipment failures, and facility-level issues. Google provides 99.9% or 99.99% SLAs for properly configured redundant Interconnect deployments.
Traffic flows through Cloud Interconnect bypass the public internet, providing predictable performance and security benefits. Private connectivity reduces exposure to internet-based attacks and provides consistent latency and throughput. This private connectivity is essential for workloads requiring guaranteed performance or handling sensitive data.
Interconnect pricing includes port fees for physical connections and egress charges for data transferred from Google Cloud to on-premises. This pricing model offers cost advantages over internet egress for high-volume data transfers. Organizations with significant hybrid cloud traffic often realize substantial cost savings compared to Cloud VPN or internet-based connectivity.
Cloud VPN creates encrypted tunnels over the public internet rather than providing dedicated physical connections. While Cloud VPN is suitable for many use cases and easier to deploy, it cannot match Cloud Interconnect’s bandwidth, latency, or consistency. For low-latency dedicated connectivity requirements, Cloud Interconnect is the appropriate solution, not Cloud VPN.
Cloud Router dynamically exchanges routes but is not itself a connectivity service. Cloud Router works in conjunction with Cloud Interconnect or Cloud VPN to manage routing but does not provide the physical or logical connections. For establishing dedicated connectivity, Cloud Interconnect is needed with Cloud Router supporting route management.
VPC Peering connects Google Cloud VPC networks within Google’s infrastructure but does not connect on-premises networks to Google Cloud. VPC Peering is for inter-VPC connectivity within Google Cloud across projects or organizations. For on-premises to cloud connectivity, Cloud Interconnect or Cloud VPN provides the necessary capabilities.
Question 17
An organization wants to implement a global load balancer that distributes HTTPS traffic to backend instances across multiple regions. Which load balancer type should be used?
A) Network Load Balancer
B) Internal Load Balancer
C) External HTTP(S) Load Balancer
D) TCP Proxy Load Balancer
Answer: C
Explanation:
The External HTTP(S) Load Balancer is a global Layer 7 load balancer that distributes HTTP and HTTPS traffic across backend instances in multiple regions, providing global anycast IP addresses, SSL termination, content-based routing, and automatic scaling capabilities. This load balancer operates at the application layer enabling intelligent traffic distribution based on URL paths, HTTP headers, or other application-level attributes. It is the ideal solution for globally distributed web applications requiring high availability, low latency, and advanced traffic management.
Global load balancing with external HTTP(S) Load Balancer uses a single anycast IP address that routes traffic to the nearest healthy backend based on geographic proximity. Google’s global network infrastructure directs users to the closest available region automatically, minimizing latency. If regional backends become unhealthy, traffic automatically fails over to other regions without DNS changes or user intervention.
Backend services define groups of backends such as instance groups, network endpoint groups, or Cloud Storage buckets that receive traffic from the load balancer. Backend services configure health checks determining backend availability, session affinity controlling traffic distribution, and timeout settings managing connection behavior. Multiple backend services can be configured allowing different URL paths to route to different backend pools.
URL maps provide content-based routing capabilities enabling sophisticated traffic distribution. URL maps define rules matching incoming request URLs to specific backend services. For example, requests to /api might route to API servers while requests to /static route to storage backends. Host rules, path matchers, and path rules create flexible routing policies based on application architecture.
SSL/TLS termination at the load balancer offloads encryption processing from backend instances improving performance and simplifying certificate management. The load balancer handles SSL negotiation with clients using Google-managed or customer-provided certificates. Backends communicate with the load balancer over HTTP or HTTPS internally, with SSL optional for backend connections based on security requirements.
Cloud CDN integration with HTTP(S) Load Balancer caches content at Google’s globally distributed edge locations, reducing latency and backend load for cacheable content. Static assets, images, videos, and other cacheable resources are served from locations near users rather than always fetching from origin servers. CDN configuration defines cache policies, cache invalidation rules, and negative caching behaviors.
Advanced features include Cloud Armor integration for DDoS protection and WAF capabilities, Identity-Aware Proxy for application-level access control, Google Cloud Armor adaptive protection against volumetric attacks, traffic director for service mesh capabilities, and serverless NEG support for Cloud Run and Cloud Functions backends. These features extend load balancer capabilities beyond basic traffic distribution.
Health checks ensure traffic routes only to healthy backends. HTTP(S) health checks send requests to configured paths and expect specific response codes. Unhealthy backends are automatically removed from load balancing until they recover. Health check configuration includes check intervals, timeout durations, healthy thresholds, and unhealthy thresholds determining backend health status.
Network Load Balancer operates at Layer 4 distributing TCP/UDP traffic based on IP protocol data rather than HTTP content. While suitable for non-HTTP traffic or when Layer 7 features are unnecessary, Network Load Balancer does not provide the HTTP-specific capabilities like URL-based routing required for many web applications. For global HTTPS traffic distribution with content-based routing, HTTP(S) Load Balancer is appropriate.
Internal Load Balancer distributes traffic within VPC networks rather than from the internet. Internal load balancers provide private load balancing for internal applications and services. For external internet-facing traffic requiring global distribution, external load balancers are necessary. Internal load balancers serve different use cases from global external load balancing.
TCP Proxy Load Balancer provides global load balancing for TCP traffic without SSL termination or HTTP-specific features. While TCP Proxy can handle any TCP traffic including HTTPS on port 443, it operates at Layer 4 without HTTP protocol awareness. For HTTPS traffic requiring Layer 7 capabilities like URL routing or HTTP header-based decisions, HTTP(S) Load Balancer provides necessary functionality.
Question 18
A company wants to ensure that traffic between VMs in the same VPC network is always routed through a firewall appliance for inspection. What should be configured?
A) VPC Peering
B) Cloud NAT
C) Custom routes with next hop as the firewall instance
D) Shared VPC
Answer: C
Explanation:
Custom routes with next hop configured as the firewall instance enable forcing traffic through firewall appliances for inspection by overriding default VPC routing behavior. By creating routes with higher priority than default routes and specifying the firewall instance as the next hop, administrators can control traffic flow requiring specific traffic patterns to traverse security appliances. This approach enables centralized security inspection, policy enforcement, and threat detection for east-west traffic within VPC networks.
Custom static routes in Google Cloud VPC define specific routing behavior overriding or supplementing automatically created routes. Each route specifies a destination IP range, next hop type, next hop reference, and priority. For firewall inspection scenarios, routes specify internal IP ranges as destinations with the firewall instance’s internal IP as the next hop. Priority values determine which route applies when multiple routes match the same destination.
Next hop types include instances, internal load balancers, VPN tunnels, or internet gateways. For firewall insertion, the next hop instance type specifies a VM instance functioning as a router or firewall. The instance must have IP forwarding enabled allowing it to receive and forward packets not addressed to itself. Without IP forwarding enabled, the instance drops packets destined for other addresses.
Multiple network interfaces on firewall instances facilitate proper traffic flow. A common design uses one interface for incoming traffic and another for outgoing traffic, creating clear separation between untrusted and trusted zones. Routes direct traffic to one interface, and the firewall instance forwards inspected traffic out another interface. This multi-NIC design enables proper ingress and egress inspection.
Symmetric routing considerations are critical for stateful firewall inspection. Traffic in both directions between sources and destinations must traverse the same firewall instance for proper session tracking. Asymmetric routing where forward and return traffic take different paths breaks stateful inspection. Route configuration must ensure both directions flow through firewalls, often requiring multiple route entries for different traffic directions.
High availability architectures for firewall inspection use redundant firewall instances with health checks and failover mechanisms. When primary firewall instances fail, routes can be updated automatically to redirect traffic to secondary instances. While Google Cloud routes are static and do not automatically failover, automation using Cloud Functions, Cloud Monitoring, and route API calls can implement failover logic.
Performance implications of routing through firewalls include added latency from additional hops, bandwidth limitations of firewall instances, and processing overhead from inspection operations. Proper sizing of firewall instances, using appropriate machine types with sufficient network throughput, and optimizing firewall rules minimize performance impact. For high-throughput environments, multiple firewall instances with load balancing distribute traffic.
Policy routing using route tags enables selective traffic inspection. By applying network tags to routes and instances, administrators control which instances’ traffic follows inspection routes. This granular control allows exempting specific traffic from inspection or applying different inspection policies to different workloads, balancing security requirements with performance and cost considerations.
VPC Peering connects separate VPC networks enabling private connectivity but does not provide traffic inspection capabilities. Peering creates direct network paths between VPCs without routing through intermediate appliances. For forcing traffic through firewall instances for inspection, custom routes rather than peering provide the necessary control.
Cloud NAT provides network address translation for instances without external IP addresses enabling internet access but does not route internal VPC traffic through inspection appliances. Cloud NAT operates at VPC boundaries for internet-bound traffic, not for east-west traffic within VPCs. Internal traffic inspection requires custom routes, not NAT.
Shared VPC allows multiple projects to use networks from a host project enabling centralized network administration but does not inherently route traffic through firewalls. While Shared VPC can be used in conjunction with custom routes for firewall insertion, Shared VPC itself is a network sharing mechanism rather than a traffic routing control. Custom routes provide the traffic steering needed for inspection.
Question 19
An organization needs to provide private Google API access to VMs that don’t have external IP addresses. What should be configured?
A) Cloud NAT
B) Private Google Access
C) VPC Peering
D) Cloud VPN
Answer: B
Explanation:
Private Google Access enables VM instances without external IP addresses to reach Google APIs and services using internal IP addresses, eliminating the need for internet connectivity or Cloud NAT for accessing Google Cloud services. This feature provides secure, private connectivity to Google APIs while maintaining the security benefits of not assigning external IPs to instances. Private Google Access is essential for security-conscious architectures where instances should not have direct internet access but still need to interact with Google Cloud services.
Private Google Access operates at the subnet level and is enabled per subnet. When enabled for a subnet, instances in that subnet without external IP addresses can reach Google APIs using the restricted.googleapis.com or private.googleapis.com IP ranges. Outbound traffic to these ranges uses internal routing within Google’s network rather than traversing the public internet, providing better security and often lower latency.
The restricted.googleapis.com VIP provides access to Google APIs while preventing instances from reaching general internet destinations. This option offers enhanced security by limiting reachable destinations to only Google APIs and services. The private.googleapis.com VIP similarly provides private API access. DNS resolution for *.googleapis.com returns these private VIP addresses when Private Google Access is enabled.
Service-specific endpoints further refine which services instances can access. For example, storage.googleapis.com for Cloud Storage, compute.googleapis.com for Compute Engine APIs, and logging.googleapis.com for Cloud Logging. DNS resolution for these service domains returns private IP addresses when Private Google Access is enabled, directing API traffic through Google’s internal network.
Configuration requirements include enabling Private Google Access on the subnet using the gcloud compute networks subnets update command with the enable-private-ip-google-access flag, ensuring DNS resolution is properly configured to return private IPs for googleapis.com domains, and verifying that firewall rules allow egress to the private Google Access IP ranges.
Private Google Access works with hybrid connectivity solutions including Cloud Interconnect and Cloud VPN. On-premises systems accessing Google APIs can use Private Google Access over these connections, benefiting from private connectivity without internet breakout. This capability enables hybrid architectures where both cloud and on-premises resources privately access Google services.
Monitoring and troubleshooting Private Google Access involves verifying subnet configuration, checking DNS resolution to confirm private IPs are returned for googleapis.com domains, reviewing VPC firewall rules for necessary egress permissions, and examining VPC Flow Logs to observe traffic patterns to Google API endpoints. Proper monitoring ensures Private Google Access operates as expected.
Use cases for Private Google Access include security-hardened environments where external IPs are prohibited, compliance requirements mandating private API access, cost optimization by avoiding Cloud NAT charges for Google API traffic, and architectures prioritizing internal routing over internet paths. These scenarios commonly benefit from Private Google Access configuration.
Cloud NAT provides network address translation enabling instances without external IPs to access the internet but is not required for Google API access when Private Google Access is enabled. Cloud NAT is appropriate for reaching internet destinations beyond Google APIs. For Google API access specifically, Private Google Access provides a more direct and cost-effective solution.
VPC Peering connects VPC networks within Google Cloud but does not provide access to Google APIs. Peering creates network connectivity between VPCs, not between VPCs and Google’s API infrastructure. For enabling API access from instances without external IPs, Private Google Access serves this specific purpose.
Cloud VPN creates encrypted connections to Google Cloud from on-premises or other clouds but does not inherently enable Private Google Access. While VPN traffic can benefit from Private Google Access when configured, VPN itself is a connectivity mechanism rather than the feature enabling private API access. Private Google Access must be explicitly enabled on subnets.
Question 20
A network engineer needs to implement a solution that translates internal IP addresses to external IP addresses for instances accessing the internet. Which service should be used?
A) Cloud Router
B) Cloud Interconnect
C) Cloud NAT
D) VPC Peering
Answer: C
Explanation:
Cloud NAT is a managed network address translation service that enables VM instances without external IP addresses to access the internet for updates, patches, and external service connectivity while maintaining security by not exposing instances directly to the internet. Cloud NAT performs source NAT translating instances’ internal IP addresses to shared external IP addresses for outbound traffic while blocking unsolicited inbound connections. This service is essential for security-hardened environments where instances should not have public IP addresses but still require internet access.
Cloud NAT operates at the regional level and is configured on Cloud Routers. Each NAT configuration specifies which subnets’ instances can use NAT, what external IP addresses to use for translation, and how to allocate ports among instances. NAT automatically scales to handle traffic volumes without manual intervention, providing reliable internet connectivity for large instance populations.
NAT IP address allocation can use automatically assigned ephemeral IPs or manually specified static external IPs. Automatic allocation simplifies management as Google Cloud handles IP provisioning, while manual allocation provides control over specific IPs used for NAT useful for whitelisting scenarios where remote services restrict access based on source IPs. Multiple external IPs can be configured to support larger instance populations.
Port allocation determines how many concurrent connections each instance can establish through NAT. Cloud NAT uses port block allocation where each instance receives blocks of source ports for its outbound connections. Default allocation provides sufficient ports for most workloads, while manual port configuration enables optimization for specific traffic patterns or troubleshooting port exhaustion issues.
Subnet selection controls which instances can use Cloud NAT. NAT configurations can include all subnets in a region, specific subnets, or specific instances using network tags. This granular control enables selective NAT application where some instances use NAT while others with external IPs connect directly, or where different NAT configurations apply to different workloads.
Logging capabilities provide visibility into NAT operations. NAT logging records translation information including internal source IPs, NAT external IPs, destination addresses, and port allocations. Log analysis helps troubleshoot connectivity issues, monitor NAT usage patterns, investigate security incidents, and optimize NAT configurations. Logs integrate with Cloud Logging for centralized analysis.
High availability is inherent in Cloud NAT’s managed design. Google Cloud automatically handles NAT gateway redundancy within regions, eliminating single points of failure. NAT continues operating through infrastructure maintenance and failures without manual intervention. For multi-region architectures, NAT is configured per region providing regional fault isolation.
Practical Cloud NAT use cases include security hardening by eliminating external IPs from instances, reducing attack surface by blocking inbound connections, controlling outbound access through NAT IP address filtering, providing internet connectivity for development and test environments, and enabling software updates and package downloads for production instances without public exposure.
Cloud Router manages dynamic routing with Cloud Interconnect and Cloud VPN but does not perform network address translation. While Cloud Router is required for Cloud NAT configuration as NAT is attached to routers, Cloud Router itself handles route exchange rather than NAT. For address translation functionality, Cloud NAT is the appropriate service.
Cloud Interconnect provides dedicated connectivity between on-premises and Google Cloud but does not perform NAT for internet access. Interconnect creates private connections to VPC networks, not internet connectivity. For translating internal IPs to external IPs for internet access, Cloud NAT serves this specific purpose.
VPC Peering connects Google Cloud VPC networks privately within Google’s infrastructure but does not provide NAT or internet access. Peering enables internal connectivity between VPCs without going through external networks. For enabling internet access with address translation, Cloud NAT is required.
Question 21
An organization wants to implement distributed denial-of-service (DDoS) protection for their applications running behind a Google Cloud load balancer. Which service provides this protection?
A) Cloud Armor
B) Cloud NAT
C) VPC Service Controls
D) Cloud Firewall
Answer: A
Explanation:
Cloud Armor provides DDoS protection and web application firewall (WAF) capabilities for applications behind Google Cloud load balancers, defending against network and application-layer attacks through Google’s global infrastructure. Cloud Armor integrates with HTTP(S) Load Balancers, SSL Proxy Load Balancers, and TCP Proxy Load Balancers, providing security policies that filter malicious traffic before it reaches backend services. This protection is essential for internet-facing applications requiring defense against volumetric attacks, application-layer exploits, and malicious bot traffic.
DDoS protection in Cloud Armor operates at multiple layers. Network-layer protection defends against volumetric attacks like UDP floods and SYN floods using Google’s massive global infrastructure to absorb attack traffic. Application-layer protection defends against HTTP floods, slowloris attacks, and other attacks targeting application logic. Adaptive Protection uses machine learning to detect and mitigate sophisticated attacks automatically.
Security policies in Cloud Armor define rules controlling traffic flow to load-balanced backends. Rules include allow or deny actions, priority values determining evaluation order, match conditions based on IP addresses, regions, or request attributes, and preview mode for testing rules without enforcement. Policies attach to backend services enabling different protection for different applications.
Preconfigured WAF rules protect against common web vulnerabilities including SQL injection attacks, cross-site scripting, local file inclusion, remote code execution, and protocol attacks. These rules implement OWASP ModSecurity Core Rule Set protections adapted for Google Cloud. Custom rules complement preconfigured rules providing application-specific protections.
IP-based access control implements geographic restrictions and IP allow/deny lists. Rules can block traffic from specific countries, allow only whitelisted IP addresses, or deny traffic from known malicious sources. IP filtering provides coarse-grained access control supplementing application-layer security measures. Named IP lists enable reusable IP address groups across multiple policies.
Rate limiting prevents abuse by limiting request rates from individual IP addresses or IP address ranges. Configurable rate limits per minute or per IP protect against brute force attacks, credential stuffing, inventory scraping, and other rate-based attacks. Exceeded rate limits result in HTTP 429 responses providing application-layer throttling.
Adaptive Protection automatically detects and mitigates application-layer DDoS attacks using machine learning analysis of traffic patterns. When attacks are detected, Adaptive Protection generates rules to block attack traffic while allowing legitimate requests. This automated response provides protection against zero-day attacks and rapidly evolving attack patterns without manual intervention.
Integration with Cloud Logging and Cloud Monitoring provides visibility into security events. Cloud Armor logs record allowed and denied requests with rule match information enabling security analysis. Metrics track request volumes, rule hits, and attack mitigation providing operational visibility. These integrations enable security monitoring, incident response, and policy optimization.
Cloud NAT provides network address translation for outbound internet connectivity but does not provide DDoS protection or WAF capabilities. Cloud NAT focuses on enabling internet access for instances without external IPs rather than defending against attacks. For DDoS protection, Cloud Armor is the appropriate service.
VPC Service Controls provide security perimeters around Google Cloud resources restricting data exfiltration but do not provide DDoS or WAF protection. Service Controls focus on data security and API access control rather than defending against network attacks. Cloud Armor and Service Controls serve complementary but different security purposes.
Cloud Firewall refers to VPC firewall rules controlling traffic to and from VM instances but does not provide load balancer-level DDoS protection or WAF features. VPC firewall rules operate at the instance level with basic IP/port filtering. For comprehensive DDoS and application-layer protection, Cloud Armor provides necessary capabilities beyond basic firewall rules.
Question 22
A company needs to monitor network traffic between VMs in their VPC for security analysis and troubleshooting. Which feature should be enabled?
A) Cloud NAT logging
B) VPC Flow Logs
C) Cloud Audit Logs
D) Firewall Rules Logging
Answer: B
Explanation:
VPC Flow Logs capture network flow information for VM instances, recording samples of network flows sent from and received by instances including source and destination IP addresses, ports, protocols, traffic volume, and timestamps. This detailed network telemetry enables security analysis, network forensics, real-time monitoring, performance optimization, and compliance auditing. VPC Flow Logs provide essential visibility into network behavior for troubleshooting connectivity issues and detecting security threats.
Flow log configuration occurs at the subnet level with options to enable or disable logging per subnet. When enabled for a subnet, flow logs capture samples of network traffic for all instances in that subnet automatically. Sampling rates and aggregation intervals are configurable, balancing visibility needs against log volume and costs. Metadata annotations provide additional context about flows enhancing analysis capabilities.
Flow log records contain comprehensive information including source and destination internal IPs, source and destination ports, IP protocol numbers, packet and byte counts, start and end timestamps, VPC network and subnet names, and additional metadata like geographical information and VM instance details. This rich data enables detailed traffic analysis and pattern identification.
Aggregation intervals control how frequently flow data is collected and exported. Shorter intervals provide near real-time visibility useful for active monitoring and rapid incident response. Longer intervals reduce log volume and costs while still providing historical traffic analysis capabilities. Five-second and one-minute intervals balance real-time needs with manageability.
Sampling rates determine what percentage of flows are captured. One hundred percent sampling captures all flows providing complete visibility but generating maximum log volume. Lower sampling rates reduce logs while still enabling statistical analysis and anomaly detection. Sampling rate selection depends on traffic volumes, analysis requirements, and budget constraints.
Export destinations include Cloud Logging for centralized log management and analysis, Cloud Storage for long-term archival and batch processing, and Pub/Sub for real-time streaming analysis. Multiple export destinations can be configured simultaneously. Integration with BigQuery enables SQL-based analysis of flow data for complex queries and trend analysis.
Use cases for VPC Flow Logs include security monitoring to detect unauthorized access attempts or data exfiltration, network troubleshooting to diagnose connectivity problems and latency issues, performance optimization to identify traffic bottlenecks and optimize routing, compliance auditing to maintain records of network communications, and cost optimization by identifying unexpected traffic patterns consuming bandwidth.
Analysis techniques include querying logs for specific source or destination IPs, analyzing traffic patterns over time, detecting anomalies like unusual traffic volumes or destinations, correlating flow logs with security events, and creating dashboards visualizing network traffic patterns. These analyses transform raw flow data into actionable insights.
Cloud NAT logging captures NAT translation information but not general VPC traffic flows. NAT logs show which internal IPs are translated to which external IPs but do not provide comprehensive network flow information for traffic not traversing NAT gateways. For complete VPC traffic visibility, VPC Flow Logs are necessary.
Cloud Audit Logs record API calls and administrative activities but not network traffic flows. Audit logs track who did what in terms of resource management but do not capture packet-level network communications. Network traffic monitoring requires VPC Flow Logs rather than Audit Logs which serve different monitoring purposes.
Firewall Rules Logging records allowed or denied connections based on firewall rules but provides less detailed information than VPC Flow Logs. Firewall logs show rule matches for specific connections but lack the comprehensive flow information including byte counts, timing details, and metadata that flow logs provide. For detailed network analysis, VPC Flow Logs offer superior visibility.
Question 23
An organization wants to establish private connectivity between two VPC networks in different projects. Which solution should be implemented?
A) Cloud VPN
B) Cloud Interconnect
C) VPC Network Peering
D) Shared VPC
Answer: C
Explanation:
VPC Network Peering connects two VPC networks allowing private RFC 1918 connectivity between them without using external IP addresses or encryption overhead. Peered networks can belong to different projects or organizations enabling cross-project and cross-organization private connectivity. This solution provides low-latency, high-bandwidth connectivity for distributed applications, shared services, multi-tenant architectures, and hybrid cloud scenarios where applications span multiple VPC networks.
VPC Peering operates as a decentralized networking mechanism where no single point of failure exists. Traffic between peered VPCs routes directly through Google’s internal network without passing through external gateways. This direct routing provides better performance and lower latency compared to VPN-based connectivity. Peering supports full mesh connectivity where multiple VPCs can peer with each other creating interconnected network topologies.
Peering establishment requires both VPC administrators to create peering connections. One administrator creates a peering connection specifying the peer network, and the other administrator accepts by creating a reciprocal connection. Both connections must be active for peering to function. This mutual consent model ensures both parties explicitly agree to network connectivity.
Subnet IP ranges in peered networks must not overlap. Overlapping IP address spaces prevent peering because routing becomes ambiguous when identical addresses exist in multiple locations. Planning non-overlapping address schemes is essential before establishing peering. Once networks are peered, adding overlapping subnets to either network causes connectivity issues.
Firewall rules in each VPC continue controlling traffic even after peering is established. Peering enables network-layer connectivity but does not automatically allow traffic. Administrators must configure appropriate ingress and egress firewall rules in each VPC to permit desired communications. This layered security model maintains control over traffic flows between peered networks.
Transitive peering is not supported in VPC Network Peering. If VPC A peers with VPC B, and VPC B peers with VPC C, VPC A and VPC C cannot communicate through VPC B. Each required connectivity path must have direct peering. This limitation affects network topology design requiring explicit peering between all VPCs that need to communicate.
Custom routes are not automatically exported across peering connections. Only subnet routes are exchanged by default. To share custom routes like routes to on-premises networks, administrators must explicitly configure route export and import policies. This control prevents unintended route propagation while enabling selective route sharing.
Monitoring peered connections uses VPC network metrics and logs. Connection status, traffic volumes between peered networks, and peering-related events appear in Cloud Console and monitoring interfaces. VPC Flow Logs capture traffic traversing peering connections enabling detailed analysis of inter-VPC communications. These monitoring capabilities ensure visibility into peered network operations.
Cloud VPN creates encrypted tunnels typically used for connecting on-premises networks to Google Cloud or connecting VPCs across regions or organizations where peering is not available. While VPN can connect VPCs, it introduces encryption overhead and is more complex than peering. For private VPC-to-VPC connectivity without encryption overhead, peering is more efficient.
Cloud Interconnect provides dedicated physical connectivity between on-premises and Google Cloud, not between VPC networks within Google Cloud. Interconnect addresses hybrid cloud connectivity requirements rather than inter-VPC communication. For connecting VPC networks, peering provides native Google Cloud connectivity without physical infrastructure.
Shared VPC allows multiple projects to use networks from a host project providing centralized network administration but does not connect separate independent VPC networks. Shared VPC is for network sharing within an organizational hierarchy rather than connecting autonomous networks. For connecting two independent VPCs, peering is appropriate.
Question 24
A network administrator needs to automate the configuration of VPN tunnels that automatically adjust routes based on network changes. What protocol should Cloud Router use?
A) OSPF
B) BGP
C) EIGRP
D) RIP
Answer: B
Explanation:
Border Gateway Protocol is the routing protocol Cloud Router uses to dynamically exchange routes with on-premises networks over Cloud VPN and Cloud Interconnect connections, providing automatic route learning and failover without manual route management. BGP is the internet’s core routing protocol enabling autonomous system interconnection and policy-based routing. Google Cloud’s implementation of BGP on Cloud Router enables hybrid cloud architectures with automatic route synchronization between on-premises and cloud networks.
Cloud Router configuration with BGP involves creating a Cloud Router instance in each region where connectivity exists, configuring BGP sessions with peer routers through VPN tunnels or Interconnect VLAN attachments, defining local and remote ASNs identifying BGP autonomous systems, and specifying advertised IP ranges that Cloud Router announces to peers. This configuration establishes dynamic routing relationships.
BGP session establishment requires matching configurations on both Cloud Router and peer routers. BGP uses TCP connections on port 179 for session communication. Peers must be directly connected through VPN tunnels or Interconnect attachments. Once sessions establish, routers exchange routing information through BGP update messages advertising available routes and path attributes.
Route advertisement from Cloud Router includes VPC subnet routes automatically advertised to on-premises peers enabling on-premises systems to reach cloud resources. Custom route advertisement enables announcing specific IP ranges including on-premises networks reached through other connections. Advertisement control provides flexibility in route propagation managing which routes are shared with peers.
Route learning from on-premises BGP peers enables Cloud Router to dynamically discover and install routes to on-premises networks. Learned routes automatically populate VPC routing tables enabling cloud instances to reach on-premises resources. As on-premises networks change, route updates propagate automatically maintaining current routing information without manual intervention.
Path attributes in BGP control route selection and traffic engineering. Attributes like AS-PATH, MED, local preference, and communities influence routing decisions. Cloud Router supports standard BGP attributes enabling sophisticated traffic engineering where administrators control inbound and outbound traffic flows through attribute manipulation. This control enables optimization for cost, performance, or redundancy.
Redundant Cloud Routers provide high availability for dynamic routing. Deploying two Cloud Routers in each region with separate VPN tunnels or Interconnect attachments to different on-premises peer routers creates redundant BGP sessions. If one router or connection fails, routing automatically converges through remaining paths. This redundancy ensures continuous connectivity despite individual component failures.
Monitoring BGP sessions through Cloud Console, gcloud commands, and Cloud Monitoring provides visibility into routing health. Session status, learned routes, advertised routes, and BGP events are observable enabling troubleshooting and verification. Alerts on BGP session failures enable rapid response to routing issues maintaining hybrid connectivity.
OSPF is a link-state routing protocol commonly used within enterprise networks but is not supported by Cloud Router. While OSPF provides dynamic routing capabilities, Google Cloud’s Cloud Router implementation uses BGP for hybrid cloud connectivity. For Cloud VPN and Interconnect dynamic routing, BGP is the supported and appropriate protocol.
EIGRP is a Cisco-proprietary distance-vector routing protocol used in Cisco-dominated networks but is not supported by Cloud Router. Google Cloud’s routing infrastructure uses standard BGP for interoperability with diverse on-premises equipment. For Cloud Router dynamic routing, BGP is required.
RIP is an older distance-vector routing protocol with limited scalability and slow convergence, not used in modern cloud environments or supported by Cloud Router. RIP’s limitations make it unsuitable for hybrid cloud scenarios. BGP’s proven scalability and policy capabilities make it the appropriate choice for Cloud Router.
Question 25
A company wants to ensure that traffic from specific VMs is routed through different network paths based on network tags. Which feature enables this functionality?
A) VPC Peering
B) Policy-based routing with network tags
C) Cloud NAT
D) Load balancing
Answer: B
Explanation:
Policy-based routing with network tags enables selective route application where custom routes are only applied to instances with specific network tags, providing granular control over traffic paths for different workloads. Network tags on routes allow administrators to implement diverse routing policies within a single VPC where different instances follow different routing rules based on their assigned tags. This capability is essential for complex architectures requiring traffic segmentation, specialized routing for specific applications, or gradual migration scenarios.
Network tags on VM instances and routes create the association enabling policy-based routing. Instances are assigned tags during creation or through modification. Routes are configured with tag parameters specifying which tags must be present for the route to apply. When an instance with matching tags sends traffic, the tagged route applies; instances without matching tags ignore the tagged route using default routing instead.
Use cases for policy-based routing include directing specific application traffic through security appliances while allowing other traffic to route normally, sending test or development traffic through different internet gateways than production traffic, routing different tenant traffic through isolated paths in multi-tenant environments, and implementing staged migrations where subsets of instances gradually move to new routing configurations.
Priority and specificity rules determine which route applies when multiple routes match a destination. More specific routes take precedence over less specific routes regardless of priority. Among equally specific routes, lower priority numbers take precedence. Network tags add another dimension where tagged routes only apply to tagged instances providing fine-grained control over route selection.
Static routes with network tags complement VPC’s default routing behavior. Default subnet routes apply to all instances automatically. Custom static routes can override default behavior for specific destinations. Adding network tags to custom routes limits their scope to tagged instances. This layered approach provides both default connectivity and selective override capabilities.
Implementation examples include tagging specific VMs with firewall-inspection tags and creating routes directing traffic from those VMs through firewall appliances, applying vpn-egress tags to instances that should send internet traffic through VPN rather than Cloud NAT, or using environment tags like production or development to implement different routing policies for different environments within the same VPC.
Operational considerations include maintaining consistent tag assignment across instances requiring similar routing, documenting tag purposes and associated routing policies, monitoring routing behavior to verify tagged routes apply as expected, and coordinating tag and route management to prevent configuration drift. Proper operational processes ensure policy-based routing achieves intended traffic control.
Troubleshooting policy-based routing involves verifying instance network tags are correctly assigned, confirming route tag specifications match instance tags, checking route priorities and specificity, and using packet capture or flow logs to observe actual routing behavior. Understanding the complete route selection algorithm enables effective troubleshooting when routing does not behave as expected.
VPC Peering connects VPC networks enabling inter-VPC communication but does not provide tag-based routing within VPCs. Peering is a connectivity mechanism rather than a routing policy tool. For selective routing based on instance tags, policy-based routing with network tags is required.
Cloud NAT provides network address translation for internet-bound traffic but does not enable tag-based routing policies. Cloud NAT can be configured per subnet but does not support per-instance or tag-based NAT selection. For traffic path control based on instance characteristics, policy-based routing provides necessary granularity.
Load balancing distributes traffic across backend instances but does not control outbound routing from VMs based on tags. Load balancers affect inbound traffic distribution while policy-based routing controls outbound traffic paths. These serve complementary but different traffic management purposes.
Question 26
An organization needs to implement a solution that prevents data exfiltration from Google Cloud services to unauthorized locations. Which service should be configured?
A) Cloud Armor
B) VPC Service Controls
C) Cloud NAT
D) VPC Firewall Rules
Answer: B
Explanation:
VPC Service Controls create security perimeters around Google Cloud resources restricting data access and movement based on context including user identity, device security posture, and network location. Service Controls prevent data exfiltration by blocking unauthorized attempts to copy data outside perimeters, controlling API access to services within perimeters, and enforcing context-aware access policies. This zero-trust approach to data security protects sensitive information in Cloud Storage, BigQuery, and other Google Cloud services from unauthorized access or exfiltration.
Service perimeters define boundaries around sets of Google Cloud resources creating protected zones. Perimeters specify included projects, accessible services, and access levels defining who can access resources under what conditions. Regular perimeters enforce restrictions immediately while dry-run perimeters enable testing policies before enforcement. Bridge perimeters enable controlled communication between isolated perimeters.
Access levels define conditions that must be met for access to be granted including IP address ranges, device security attributes, user identity and group membership, and time of access. Access levels combine conditions using AND/OR logic creating sophisticated context-aware policies. For example, access might require corporate network origin AND compliant device AND specific user group membership.
Restricted VIP access forces API clients to use VPC Service Controls-restricted VIPs rather than standard googleapis.com VIPs. This enforcement prevents circumventing service perimeters by routing through public internet paths. Restricted VIP access is essential for comprehensive perimeter enforcement ensuring all API traffic is subject to perimeter controls.
Ingress and egress policies control data movement across perimeter boundaries. Ingress policies govern requests from outside perimeters to resources inside perimeters. Egress policies control requests from inside perimeters to resources outside. These directional policies enable fine-grained control over cross-perimeter communications allowing necessary legitimate access while blocking unauthorized data movement.
Supported services within perimeters include Cloud Storage for object storage, BigQuery for data warehouse, Cloud Bigtable for NoSQL database, Cloud Spanner for relational database, and many other Google Cloud services. Each service can be included in perimeters with policies controlling access. Coverage expansion continues as more services add Service Controls support.
Audit logging records all access decisions including allowed and denied requests, access level evaluations, and perimeter boundary crossings. These logs provide visibility into data access patterns, enable security monitoring and incident response, and support compliance auditing. Integration with Cloud Logging and Security Command Center provides centralized security visibility.
Implementation best practices include starting with dry-run mode to test policies without enforcement, gradually restricting access levels tightening policies incrementally, monitoring access patterns to identify legitimate use cases requiring exceptions, documenting perimeter designs and access policies, and regularly reviewing and updating policies as requirements evolve. Careful implementation prevents disrupting legitimate operations while enhancing security.
Cloud Armor protects applications from DDoS attacks and web exploits but does not prevent data exfiltration from cloud services. Cloud Armor focuses on incoming threats to application endpoints rather than controlling data movement from storage and database services. For data exfiltration prevention, VPC Service Controls provide necessary capabilities.
Cloud NAT enables internet access for instances without external IPs but does not control data exfiltration from Google Cloud services. Cloud NAT focuses on network address translation for internet connectivity rather than securing data in storage and database services. Data protection requires VPC Service Controls rather than network address translation.
VPC Firewall Rules control network traffic to and from VM instances at the network layer but do not secure data in Google Cloud services like Cloud Storage or BigQuery. Firewall rules address network security while VPC Service Controls address data security. Preventing data exfiltration from cloud services requires Service Controls capabilities beyond network-layer filtering.
Question 27
A company wants to configure automatic failover between two Cloud VPN tunnels connecting to their on-premises network. What must be configured to enable this functionality?
A) Static routes only
B) Cloud Router with BGP dynamic routing
C) Multiple external IP addresses
D) VPC Peering
Answer: B
Explanation:
Cloud Router with BGP dynamic routing enables automatic failover between redundant Cloud VPN tunnels by dynamically adjusting routes based on tunnel health and automatically withdrawing routes for failed tunnels while advertising routes through healthy tunnels. Without dynamic routing, static routes continue directing traffic to failed tunnels until manual intervention occurs. BGP provides the automatic detection and reaction necessary for seamless failover maintaining connectivity during tunnel or gateway failures.
Redundant VPN topology for high availability involves creating at least two VPN tunnels from Google Cloud to on-premises, connecting to different on-premises peer gateways from different Google Cloud VPN gateways, and configuring Cloud Router BGP sessions through each tunnel. This redundancy protects against tunnel failures, gateway failures, and peer failures providing multiple independent paths between cloud and on-premises networks.
BGP session monitoring detects tunnel failures through BGP keepalive mechanisms. When tunnels fail, BGP sessions over those tunnels go down. Cloud Router detects session failures and automatically withdraws routes that were learned through failed sessions. Remaining sessions continue advertising routes enabling traffic to flow through surviving paths. This automatic response occurs within seconds without administrative intervention.
Active-active configurations utilize all available tunnels simultaneously distributing load across multiple paths. BGP advertises the same routes through all tunnels with equal preference. Equal-cost multi-path routing sends traffic across all available tunnels balancing load. When tunnels fail, traffic shifts to remaining tunnels automatically without disruption beyond brief convergence periods.
Active-passive configurations keep backup tunnels idle during normal operations. BGP route preferences using AS-PATH prepending or MED manipulation make certain routes less preferred than others. Traffic uses primary tunnels during normal operations and automatically fails over to backup tunnels when primary paths fail. This configuration provides redundancy while maintaining predictable primary paths.
Convergence time for failover depends on BGP timer configuration. Default BGP timers provide convergence in tens of seconds. Aggressive timer tuning can reduce convergence to seconds but increases protocol overhead and sensitivity to transient failures. Timer selection balances failover speed against stability and reliability requirements.
Monitoring failover health involves observing BGP session states, tracking route advertisements and withdrawals, measuring failover timing during planned and unplanned outages, and alerting on tunnel or session failures. Regular testing verifies failover functions correctly ensuring redundancy provides expected protection. Monitoring and testing validate high availability architectures.
Coordination with on-premises routing infrastructure ensures end-to-end automatic failover. On-premises routers must also use BGP for dynamic routing with cloud endpoints. Static routing on either end prevents automatic failover even if the other end uses dynamic routing. Both sides must participate in dynamic routing for complete automatic convergence.
Static routes require manual updates when tunnels fail and do not enable automatic failover. Administrators must detect failures and manually update routes to redirect traffic to surviving tunnels. This manual process introduces downtime and operational burden. For automatic failover, dynamic routing with BGP is essential.
Multiple external IP addresses provide address redundancy but do not enable automatic routing failover. Address diversity is important for gateway redundancy but without dynamic routing to adjust route advertisements, traffic continues attempting failed paths. External IP redundancy complements but does not replace BGP-based automatic failover.
VPC Peering connects VPC networks for inter-VPC communication but does not enable VPN tunnel failover. Peering is unrelated to hybrid connectivity and failover requirements. For automatic VPN failover, Cloud Router with BGP provides necessary dynamic routing capabilities.
Question 28
A network engineer needs to implement centralized management of firewall rules across multiple VPC networks in different projects. Which solution provides this capability?
A) VPC firewall rules
B) Hierarchical firewall policies
C) Cloud Armor
D) Network tags
Answer: B
Explanation:
Hierarchical firewall policies enable centralized firewall rule management at organization or folder levels that apply to all VPCs within those organizational nodes, providing consistent security posture across multiple projects and enforcing organization-wide security standards. Hierarchical policies complement VPC-level firewall rules with policies inherited from parent nodes in the resource hierarchy. This hierarchical approach enables security teams to manage critical security rules centrally while allowing project teams to manage project-specific rules within bounds of organizational policies.
Policy hierarchy in Google Cloud follows the resource hierarchy from organization to folders to projects. Hierarchical firewall policies can be created at organization level applying to all resources, at folder level applying to projects within folders, or at VPC level applying to specific networks. Policies at higher levels are inherited by lower levels with evaluation occurring from top to bottom. This inheritance enables central control with local flexibility.
Rule evaluation order for firewall policies proceeds from highest to lowest priority across all applicable policy layers. Hierarchical organization policies evaluate first, followed by folder policies, then VPC network policies. Within each policy, rules evaluate by priority number with lower numbers evaluated first. The first matching rule determines whether traffic is allowed or denied. This deterministic evaluation provides predictable traffic control.
Use cases for hierarchical policies include enforcing baseline security rules across all organization resources preventing projects from creating overly permissive rules, implementing regulatory compliance requirements uniformly, managing DMZ or security zone rules centrally, preventing specific high-risk protocols organization-wide, and enabling security teams to control critical rules while delegating routine rule management to project teams.
Rule structure in hierarchical policies matches VPC firewall rule structure including direction ingress or egress, action allow or deny, priority determining evaluation order, match conditions based on IP ranges, protocols, and ports, and target specification using service accounts or network tags. Familiarity with VPC firewall rules translates directly to hierarchical policies with added hierarchical management benefits.
Preview mode enables testing hierarchical policies before enforcement. Preview mode logs what actions policies would take without actually enforcing them. Administrators can analyze logs to verify policies match intentions and do not break legitimate traffic flows. After validation, policies can be enforced. Preview mode reduces risk of unintended disruption from policy changes.
Monitoring hierarchical policies uses Firewall Insights and firewall rules logging providing visibility into rule usage and traffic patterns. Unused rules, overly permissive rules, and shadowed rules can be identified and remediated. Logs show which hierarchical policies allowed or denied specific connections enabling troubleshooting and security analysis.
Organizational coordination is important for hierarchical policy success. Clear responsibility definitions between central security teams managing hierarchical policies and project teams managing VPC rules prevent conflicts and gaps. Documentation of hierarchical policies and their purposes helps project teams understand constraints and work within them effectively.
VPC firewall rules operate at individual VPC network level requiring management within each VPC separately. While effective for individual network security, VPC rules lack centralized cross-project management capabilities. For managing rules across multiple VPCs and projects centrally, hierarchical policies provide necessary centralization.
Cloud Armor protects applications behind load balancers from DDoS and web exploits but does not manage firewall rules for VM instances. Cloud Armor operates at load balancer edge with different purposes than VPC network firewalls. For VM network-level firewall rule management, hierarchical policies serve this purpose.
Network tags enable selective rule application within VPCs but do not provide centralized cross-project rule management. Tags are used within firewall rules for targeting but do not themselves enable hierarchical policy management. For centralized policy enforcement across projects, hierarchical firewall policies are required.
Question 29
An organization wants to set up internal DNS resolution that allows VMs in one VPC to resolve DNS names of VMs in a peered VPC. What DNS configuration is required?
A) Cloud DNS forwarding
B) DNS peering between VPCs
C) External DNS server
D) Custom DNS resolver
Answer: B
Explanation:
DNS peering enables private DNS name resolution across VPC Network Peering connections allowing instances in one VPC to resolve DNS names of instances in peered VPCs. This capability is essential for multi-VPC architectures where applications are distributed across networks and need to discover each other using DNS names rather than hard-coded IP addresses. DNS peering provides seamless name resolution consistent with network connectivity established through VPC peering.
DNS peering configuration involves enabling DNS resolution for VPC peering connections in both directions. When creating or modifying VPC peering, options control whether DNS queries can be sent to the peer network and whether peer DNS queries can be resolved locally. Bidirectional DNS peering requires enabling export and import settings in both peering connections. This configuration synchronizes DNS behavior with network connectivity.
Private DNS zones in Cloud DNS can be shared across peered VPCs through DNS peering. Zones created in one VPC automatically become queryable from peered VPCs when DNS peering is enabled. This sharing enables centralized DNS management where one VPC hosts DNS zones serving multiple peered networks. Alternatively, each VPC can maintain its own zones with peering enabling mutual resolution.
Name resolution priority affects which answers instances receive when multiple sources can provide responses. Internal DNS servers provided by Google Cloud, custom Cloud DNS zones, and DNS peering all interact to serve queries. Understanding resolution order helps predict DNS behavior in complex environments with multiple DNS sources and peered networks.
Managed DNS forwarding policies provide additional control over DNS resolution paths. While DNS peering handles peered VPC resolution, forwarding policies can direct specific domain queries to designated DNS servers. Combining DNS peering with forwarding policies enables sophisticated DNS architectures supporting hybrid environments with both cloud-native and on-premises DNS infrastructure.
Split-horizon DNS configurations use DNS peering to provide different DNS responses to internal versus external clients. Private zones accessible through DNS peering can provide internal IP addresses for services while external clients receive public IP addresses from public DNS zones. This approach maintains security while enabling flexible service access.
Monitoring DNS resolution across peered VPCs involves examining Cloud DNS query logs, troubleshooting resolution failures by verifying DNS peering configuration, checking Cloud DNS zone configurations, and ensuring VPC peering itself is active. DNS troubleshooting requires understanding the complete resolution path including peering, zones, and forwarding policies.
DNS peering limitations include not supporting transitive resolution where if VPC A peers with B and B peers with C, A cannot resolve C’s names through B. Each VPC needing to resolve names across peering must have direct peering relationships established. This constraint affects DNS architecture design in multi-VPC environments requiring careful planning of peering topology.
Cloud DNS forwarding sends queries to specified DNS servers but does not automatically enable resolution across VPC peering. Forwarding is used primarily for hybrid scenarios directing queries to on-premises DNS rather than cross-VPC resolution. For VPC peering DNS, DNS peering configuration rather than forwarding provides needed functionality.
External DNS servers can be configured as custom resolvers but do not provide the native integration and automatic configuration that DNS peering offers. External DNS requires manual configuration maintaining server information and does not leverage built-in Cloud DNS and VPC peering integration. Native DNS peering provides simpler and more integrated cross-VPC resolution.
Custom DNS resolver implementation is more complex than native DNS peering and loses benefits of managed Cloud DNS. While possible to deploy custom DNS servers, DNS peering provides this capability natively without managing additional infrastructure. For standard cross-VPC DNS resolution, DNS peering is the appropriate and simpler solution.
Question 30
A company needs to ensure that only authorized Google Cloud services can access resources in their VPC. Which feature restricts API access based on service identity?
A) VPC Firewall Rules
B) VPC Service Controls
C) IAM Service Account permissions
D) Private Google Access
Answer: C
Explanation:
IAM Service Account permissions control what operations service accounts can perform on Google Cloud resources, enabling fine-grained authorization for automated processes and services. Service accounts represent applications or services rather than individual users, providing identities for code running on VMs, Cloud Functions, Cloud Run, and other compute services. Properly configured service account permissions ensure only authorized services access specific resources implementing principle of least privilege for automated workloads.
Service accounts are special Google accounts that represent applications or services rather than end users. Each service account has an email address serving as its identity and is associated with cryptographic keys used for authentication. Service accounts can be granted IAM roles just like user accounts, and resources can verify service account identities when granting access to API calls.
Default service accounts are automatically created for many Google Cloud services including Compute Engine default service account and App Engine default service account. While convenient, default service accounts often have broad permissions that violate least privilege principles. Best practices recommend creating custom service accounts with specific permissions tailored to each workload’s actual requirements rather than using default accounts.
Custom service accounts enable implementing precise least-privilege access control. Administrators create service accounts for specific purposes, grant only necessary IAM roles, and assign service accounts to compute resources performing those functions. For example, a service account for backups would have storage write permissions but no compute or networking permissions. This granular approach minimizes potential damage from compromised service accounts.
IAM roles granted to service accounts should be as specific as possible. Predefined roles provide common permission sets for specific job functions. Custom roles enable even finer granularity granting only exact permissions needed. Regular role audits ensure service accounts maintain appropriate permissions as requirements evolve and permissions are removed when no longer needed.
Service account keys enable authentication outside Google Cloud infrastructure but create security risks if compromised. Keys should be rotated regularly, stored securely, and avoided when possible in favor of using workload identity federation or other keyless authentication methods. Monitoring key usage and restricting key creation prevent key-related security incidents.
Workload identity federation enables resources outside Google Cloud to authenticate as service accounts without long-lived keys. External identities from AWS, Azure, or on-premises systems can be mapped to Google Cloud service accounts. This federation provides secure authentication without managing and distributing service account keys reducing security risks.
Service account impersonation allows one service account or user account to temporarily act as another service account. This capability enables privilege elevation for specific operations without permanently granting high permissions. Impersonation should be carefully controlled with IAM conditions limiting when and how impersonation can occur preventing abuse while enabling necessary elevation scenarios.
VPC Firewall Rules control network traffic at IP and port level but do not verify service identities or authorize API access. Firewall rules determine which network connections are allowed based on source/destination IP, protocol, and port. For controlling resource access based on service identity and required operations, IAM service account permissions provide necessary authorization.
VPC Service Controls restrict data movement based on perimeters and access levels but do not directly manage service-to-resource authorization within permitted perimeters. Service Controls focus on preventing data exfiltration while IAM focuses on who can perform what operations. Both serve complementary security purposes with IAM providing fundamental authorization.
Private Google Access enables API access from instances without external IPs but does not control authorization. Private Google Access provides network-level connectivity to Google APIs while IAM service account permissions control authorization for those API calls. Network access and resource authorization are separate security layers both necessary for complete access control.