Linux DNS redundancy

What this Scenario does

This Scenario blocks DNS traffic on your Linux hosts, simulating a primary DNS provider failure. This tests whether your Linux systems' DNS resolver configuration (such as /etc/resolv.conf) correctly falls back to secondary DNS providers.

‍

Why run this Scenario?

DNS can fail in many ways, including:

• Failures in nameservers and/or recursive resolvers, causing DNS queries to time out or return errors.
• Network saturation (or a DDoS attack) slowing down DNS queries or causing them to drop.
• Misconfigured Quality of Service (QoS) rules, causing the network to de-prioritize DNS traffic.

Running this Scenario can help:

• Verify that Linux DNS resolver configuration supports failover to secondary DNS providers.
• Validate DNS caching behavior and TTL settings on your Linux infrastructure.
• Identify services that hard-code DNS server addresses instead of using system-level resolution.
• Ensure that DNS failures on Linux hosts don't cascade into application-level outages.

‍

Expected outcome

If the primary DNS provider fails, services running on Linux hosts continue resolving DNS queries through secondary providers with no interruption.