Google Professional Cloud Network Engineer Practice Test - Questions Answers, Page 18

Understanding VPC Flow Logs:

VPC Flow Logs is a feature that captures information about the IP traffic going to and from network interfaces in a VPC. It helps in monitoring and analyzing network traffic, ensuring security, and optimizing network performance.

Current Configuration:

According to the diagram, VPC Flow Logs is already configured for Subnet-1 in the host VPC. This means that traffic information for Subnet-1 is being captured and logged.

Requirement for Subnet-2:

The goal is to monitor flow logs for Subnet-2, which is in the service project VPC.

Correct Configuration for Subnet-2:

To monitor the flow logs for Subnet-2, you need to configure VPC Flow Logs within the service project VPC where Subnet-2 resides. This is because VPC Flow Logs must be configured in the same project and VPC where the subnet is located.

Implementation Steps:

Go to the Google Cloud Console.

Navigate to the service project where Subnet-2 is located.

Select the VPC network containing Subnet-2.

Enable VPC Flow Logs for Subnet-2 by editing the subnet settings and enabling the flow logs option.

Cost and Performance Considerations:

Enabling VPC Flow Logs may incur additional costs based on the volume of data logged. Ensure to review and understand the pricing implications.

Analyze and manage the data collected to avoid unnecessary logging and costs.

Google Cloud VPC Flow Logs Documentation

Configuring VPC Flow Logs

Shared VPC Overview

By configuring VPC Flow Logs in the service project VPC for Subnet-2, you ensure that traffic data is correctly captured and monitored, adhering to Google Cloud's best practices.

Create Packet Mirroring Policies:

You need to create three packet mirroring policies, one for each zone (us-west2-a, us-west2-b, and us-west2-c). This ensures that each zone's traffic is mirrored appropriately without unnecessary cross-zone traffic.

Create Collector Instances:

Set up one group of collector instances for the us-west2 region. Having a single group of collector instances for the entire region minimizes the number of instances required and simplifies the management while keeping egress costs low since the collectors are within the same region.

Configuration of Policies:

Each packet mirroring policy should be configured to match traffic for its specific zone. Use instance-tags to identify and match the relevant instances within each zone. This helps in correctly capturing the traffic from the appropriate sources.

Filter for TCP Traffic:

Create a filter for TCP traffic (ports 80 and 443). This step ensures that only the relevant web application traffic is mirrored, reducing the amount of data processed and improving efficiency.

Cost Efficiency:

By having packet mirroring policies specific to each zone and a regional collector group, you reduce inter-zonal network egress costs. The data remains within the same region, avoiding extra charges associated with cross-zone traffic.

Google Cloud Packet Mirroring Documentation

Best Practices for Packet Mirroring

Cost Management in Google Cloud

This solution aligns with Google-recommended practices by ensuring efficient traffic capture, minimal inter-zonal costs, and streamlined management of the packet mirroring setup.

For secure traffic over Cloud Interconnect, you configure an HA VPN gateway to work with existing VLAN attachments and use the same Cloud Router. This setup integrates seamlessly, leveraging the established BGP sessions for VPN tunnel configurations.

Cloud NGFW Enterprise provides TLS inspection to detect and manage threats within encrypted traffic. Configuring firewall rules for TLS inspection enables granular monitoring and filtering, ensuring secure internet traffic.

Using a Shared VPC enables centralized network management and efficient resource access by service projects. This scalable setup supports isolated environments for each team while allowing the network team to manage network policies and resources in a host project.

Enabling Private Google Access on the subnet allows VMs to access Google APIs (like Cloud Storage and BigQuery) directly, without routing traffic over the internet. This approach is cloud-native and involves minimal setup, aligning with a cloud-first strategy.

For the Dedicated Interconnect to be the primary connection over the HA VPN, you should:

Enable global dynamic routing mode to allow the VPC to distribute routes dynamically across regions.

Set the BGP priority for the VLAN attachments associated with the Dedicated Interconnect to a lower base priority (e.g., 100) than the HA VPN's priority (e.g., 20000) to ensure it is preferred.

Setting up global dynamic routing with adjusted BGP priorities on both Interconnect and VPN will allow dynamic routing of traffic based on set preferences and path attributes, such as MED and priority levels. This setup ensures the Dedicated Interconnect, with a lower priority value, becomes the primary path for traffic, while the HA VPN, with a higher priority, serves as a backup.

To control internet access on a per-URL basis (including hostname and path), you should deploy Secure Web Proxy with global access enabled. The Secure Web Proxy will allow policy-based filtering of web traffic, allowing control over which URLs can be accessed based on the URL list defined in the policy. Unlike Cloud NAT, which does not support FQDN filtering, Secure Web Proxy is designed to provide such control, especially for scenarios with sensitive or controlled internet access requirements.

When troubleshooting connectivity issues, especially over public internet connections with intermittent errors, Connectivity Tests in Network Intelligence Center are crucial. This tool allows you to simulate the connectivity and understand the data plane status of Google Cloud resources. Since ICMP tests pass but TCP tests fail intermittently, using Connectivity Tests with TCP parameters will provide detailed insight into possible network issues like route misconfigurations, peering issues, or other transient problems affecting only specific protocols.