Press release

NS1 Creates Open Source Tool for Testing DNS Performance and Functionality

Sponsored by Businesswire

the leader in next-generation DNS and traffic management solutions,
today announced the availability of Flamethrower, a lightweight,
configurable open source tool for functional testing, benchmarking, and
stress testing DNS servers and networks. Flamethrower is available on GitHub.

As the first stop for all application traffic, DNS performance and
resiliency are critical to modern application delivery. The need for
monitoring and testing DNS capabilities has grown in importance, but
while building its new DNS servers, NS1 found existing tools didn’t
allow for realistic traffic patterns and real-world testing environments.

“Like many popular open source tools, Flamethrower was created to
address a need we had internally at NS1,” said Shannon Weyrick, vice
president of architecture at NS1. “Our engineering team required a
versatile tool for DNS server development and load testing, but existing
solutions didn’t have the features we needed, which limited our ability
to perform realistic tests. We built Flamethrower to enable complex
testing for DNS performance and functionality so that traffic teams can
gain a better understanding of the impact of potential changes to
applications and infrastructure in actual production situations.”

Flamethrower supports IPv4, IPv6, UDP, TCP, DNS over TLS, as well as
experimental support for DNS over QUIC. It has a modular system for
generating the queries used in the tests, allowing for rich and
realistic test scenarios that can plug into automation pipelines. It
simulates multiple concurrent clients and generates actionable metrics,
including send and receive counts, timeouts, errors and data on minimum,
maximum and average latency. The metric output format is suitable for
ingestion into databases, such as Elastic, for further processing or

Early testers within the open source community, including Sara Dickinson
of Sinodun
, have offered positive feedback about the new tool.

“We are delighted to see an open source effort on a new DNS performance
tool, and especially because Flamethrower was designed from the ground
up to support multiple transport protocols for DNS rather than being UDP
centric,” Dickinson said. “The recent rapid development of new
transports for DNS makes Flamethrower a valuable tool for implementors
and operators to evaluate the latest DNS software.”

Flamethrower can adjust its queries per second flow over time, which is
useful for generating a “signal” of traffic (e.g., a square wave) for
calibrating time series metrics collection. It can also be used to mimic
the surges in traffic an organization might see during a DDoS attack or
stress test systems for failover, making it an ideal tool for wargaming
and chaos

Casey Rosenthal, a renowned
, chaos engineering expert, and former engineering manager for
the Traffic and Chaos Teams at Netflix, said Flamethrower’s ability to
replicate realist traffic patterns provides substantial value to traffic

“I wish this tool had been available when I managed traffic teams; we
could have used this to validate our methodologies for regional
failover,” said Rosenthal, who now serves as CEO and co-founder for

Flamethrower can be built from source, and is available via several OS
packaging systems and on Docker Hub. As it’s an open source project,
community contributions are welcome and encouraged. The source code is
hosted on GitHub
alongside other DNS-related tools at the DNS-OARC (Operations, Analysis,
and Research Center) community. Visit the NS1
for a more detailed review of the Flamethrower tool.

About NS1

NS1 is the leader in next-generation DNS and traffic management
solutions that orchestrate the delivery of the world’s most critical
internet and enterprise applications. Only NS1’s purpose-built platform,
which is built on a modern API-first architecture, transforms DNS into
an intelligent, efficient and automated system, driving dramatic gains
in reliability, resiliency, security and performance of application
delivery infrastructure. Many of the highest-trafficked sites and
largest global enterprises trust NS1, including Salesforce, LinkedIn,
Dropbox, Nielsen, Squarespace, Pandora and The Guardian. Visit
to learn more.