Routes and routing in GCP - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding GCP Route Priorities

You have two routes in Google Cloud Platform (GCP) with the same destination range but different priorities. Route A has priority 1000 and Route B has priority 500. Which route will GCP use to send traffic to that destination?

A Route B because it has a lower priority number.

B Route A because it was created first.

C Route A because it has a higher priority number.

D GCP will load balance traffic evenly between Route A and Route B.

💡 Hint

In GCP routing, lower priority numbers mean higher priority.

GCP uses the route with the lowest priority number to send traffic. So Route B with priority 500 is preferred over Route A with priority 1000.

❓ Configuration

intermediate

Configuring a Custom Static Route in GCP

You want to create a static route in GCP that directs traffic destined for 10.0.0.0/16 to a specific VM instance acting as a gateway. Which next hop type should you specify in the route configuration?

A Next hop IP address

B Next hop VPN tunnel

C Next hop instance

D Next hop internet gateway

💡 Hint

The next hop should be the VM instance acting as the gateway.

To route traffic through a specific VM instance, you specify the next hop as that instance in the route configuration.

❓ Architecture

advanced

Designing a Multi-Region Network with Custom Routes

You have two VPC networks in different regions connected via VPC peering. You want to ensure that traffic from region A to region B uses a specific firewall VM in region A as a gateway before reaching region B. Which routing approach achieves this?

A Create a custom static route in region A VPC with next hop instance set to the firewall VM and destination range of region B's subnet.

B Set up a VPN tunnel between the two regions and route traffic through it.

C Use dynamic routing with Cloud Router to automatically route traffic through the firewall VM.

D Use default routes and rely on VPC peering to handle traffic automatically.

💡 Hint

Custom static routes can direct traffic through specific instances.

By creating a custom static route with the firewall VM as next hop, traffic to region B is forced through the firewall VM in region A.

❓ security

advanced

Impact of Routes on Firewall Security in GCP

You have a firewall rule allowing traffic from subnet A to subnet B. However, traffic is still blocked. You discover a route that sends subnet B traffic through a different gateway that blocks the traffic. What is the best way to fix this routing issue to allow traffic flow?

A Disable the firewall rule and rely on routes to control traffic.

B Increase the priority of the firewall rule to override the route.

C Delete the conflicting route that sends traffic through the blocking gateway.

D Create a new route with a lower priority number that directs traffic through the correct gateway.

💡 Hint

Routes with lower priority numbers take precedence.

Creating a new route with a higher priority (lower number) that directs traffic through the correct gateway ensures traffic flows as intended without deleting existing routes.

❓ service_behavior

expert

Behavior of GCP Routes with Overlapping Destination Ranges

You have two routes in GCP with overlapping destination IP ranges: Route X with destination 10.0.0.0/16 and priority 1000, and Route Y with destination 10.0.0.0/24 and priority 1100. A VM sends traffic to IP 10.0.0.50. Which route will GCP use and why?

A Route X because it has a lower priority number.

B Route Y because it has a more specific destination range.

C Route X because it was created first.

D Route Y because it has a higher priority number.

💡 Hint

GCP prefers the most specific route regardless of priority.

GCP selects the route with the most specific destination range (longest prefix match) first, then uses priority if there is a tie. Here, 10.0.0.0/24 is more specific than 10.0.0.0/16, so Route Y is used.