FAQ

DNS

Why is my ISP’s DNS not the fastest?

Local ISP DNS often has caching advantages but may lack a global anycast network, DNSSEC validation, privacy features (DoH/DoT), and reliability guarantees. Test both with net-benchmark dns compare and decide based on your priorities.

How often should I benchmark DNS?

When choosing a provider (one-time, 3+ iterations), monthly for network health checks, before and after migrating providers, and on-demand when troubleshooting slow requests.

Can I test my own DNS server?

Yes. Add it to a custom JSON file:

{ "resolvers": [{ "name": "My DNS", "ip": "192.168.1.1" }] }

Then: net-benchmark dns benchmark --resolvers my-resolvers.json --use-defaults

What does DNSSEC_FAILED mean?

The resolver did not return a valid DNSSEC signature (AD flag) for the queried domain. This is expected for unsigned domains — only ~33% of commonly tested domains are DNSSEC-signed.

Why do results vary between runs?

Network congestion, DNS caching at the resolver and intermediate hops, server load fluctuations, and geographic anycast routing decisions all contribute. Run --iterations 5 and compare median latency for stable results.

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HTTP

Why is my API slower than expected?

The timing breakdown (DNS → TCP → TLS → TTFB → TTLB) tells you exactly where the time goes. If DNS is slow, check your resolver. If TLS is slow, check certificate chain size or OCSP stapling. If TTFB is slow, the server logic or database is the bottleneck.

Can I test endpoints behind authentication?

Yes — --auth basic:user:pass, --auth bearer:token, or --headers x-api-key:key all work. mTLS is also supported via --cert and --cert-key.

How often should I benchmark HTTP endpoints?

One-time when choosing a CDN or API provider, daily for critical production endpoints, before deployment to catch performance regressions, and after incidents to validate fixes.

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General

PDF export fails — what should I do?

Install WeasyPrint and its system-level C dependencies. See Installation for WeasyPrint setup. Or skip PDF: --formats csv,excel.

Command not found after install?

pip install -e .
python -m net_benchmark.dns_benchmark.cli --help   # DNS fallback
python -m net_benchmark.http_bench.cli --help      # HTTP fallback

Make sure the Python bin / Scripts directory is in your PATH.

Is this tool safe to use in production?

Yes. It only performs standard DNS lookups and HTTP read requests. It does not modify DNS records, modify data on servers, perform attacks, or send data to external servers beyond the queries themselves.