ND-300 Network Diagnostic

Cross-platform network diagnostic tool for Windows, macOS, and Linux. Includes SpeedQX, a standalone quad-provider speed test.

Features

Two operating modes: User mode (clean summary) and Technician mode (deep diagnostics)
8 core diagnostics: adapters, interfaces, gateway, DNS, public IP, latency, speed test, port connectivity
18 deep diagnostics (technician mode): ARP, routing, connections, listening ports, DHCP, protocol stats, adapter hardware, proxy, VPN, firewall, DNS cache, IPv6, MTU, connection states, bufferbloat, reverse DNS, TLS inspection, traffic counters
Diagnostic-driven nd300 fix — runs the diagnostics, identifies which checks failed, and applies only the recovery actions that target those specific failures. Clean and latency-only networks are advisory/no-op, DNS repair is staged from safest to most invasive, and medium/high-risk steps require confirmation. Re-tests after each step and repeats until everything passes or no further actions remain.
Quad-provider speed test — Cloudflare + M-Lab NDT7 + LibreSpeed + fast.com (Netflix) with bounded N-provider inverse-variance aggregation, modified trimean (Ookla-style), and RFC 3550 jitter for technician-grade accuracy. Measures ping, jitter, download, upload, packet loss, stability, and provider divergence.
Resilient self-update — nd300 update / speedqx update checks GitHub for the latest release and runs a probe-and-retry chain: cargo first when available, cargo-dist installer as universal fallback (curl → wget on macOS/Linux, PowerShell → pwsh on Windows). On Windows it can also upgrade in place via the matching first-class installer (MSI/EXE × Global/Corporate), chosen from an install marker, with SHA-256 verification of the download (refuse-on-mismatch). It cleans up shadowing non-Cargo ND300 installs when migrating to cargo install nd300, verifies the new version actually landed, and surfaces per-strategy failures with specific reasons.
SpeedQX standalone speed test binary — all 4 providers with per-provider breakdown and real-time progress
Bufferbloat detection with grade scoring (A+ through F)
JSON output for scripting and automation
Unicode box-drawing table rendering with ASCII fallback
Color-coded status indicators (OK/Warn/Fail/Skip)
Cross-platform — native support for Windows, macOS, and Linux

Installation

Shell (macOS/Linux)

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/QubeTX/qube-network-diagnostics/releases/latest/download/nd300-installer.sh | sh

PowerShell (Windows)

powershell -ExecutionPolicy Bypass -c "irm https://github.com/QubeTX/qube-network-diagnostics/releases/latest/download/nd300-installer.ps1 | iex"

Windows installers (MSI + EXE, Global + Corporate)

Four first-class Windows installers are attached to every release. All four install both nd300.exe and speedqx.exe and add the install dir to your PATH. Pick one format per edition (installing two formats of the same edition leaves duplicate Add/Remove Programs entries).

Edition	Scope	Admin (UAC)?	Installs to	Download
Global MSI	Per-machine	Yes	`C:\Program Files\nd300\bin\`	`nd300-x86_64-pc-windows-msvc.msi`
Corporate MSI	Per-user	No	`%LocalAppData%\Programs\nd300\bin\`	`nd300-x86_64-pc-windows-msvc-corporate.msi`
Global EXE	Per-machine	Yes	`C:\Program Files\nd300\bin\`	`nd300-x86_64-pc-windows-msvc-setup.exe`
Corporate EXE	Per-user	No	`%LocalAppData%\Programs\nd300\bin\`	`nd300-x86_64-pc-windows-msvc-corporate-setup.exe`

Corporate editions install per-user with no admin prompt — ideal for locked-down corporate machines where you can't elevate.
Each installer writes a small HKCU\Software\ND300\InstallSource marker so nd300 update knows which installer to re-download for an in-place upgrade (see Self-Update).
Each installer has a .sha256 sidecar; nd300 update verifies it before running the downloaded installer (refuse-on-mismatch).
The cargo-dist PowerShell installer above remains available and installs into Cargo's bin directory.

One install at a time — automatic consolidation. Each installer offers two clean-up checkboxes, both checked by default:

Remove an older Cargo-installed copy — deletes a shadowing nd300/speedqx in your ~\.cargo\bin (a prior cargo install copy usually wins on PATH otherwise). Your Rust toolchain is never touched — cargo.exe, rustup.exe, and the .cargo\bin PATH entry are left exactly as they were.
Also remove the other edition — deletes the other Windows edition (Global ↔ Corporate) so only one edition remains.

The clean-up only ever removes nd300.exe/speedqx.exe, never the copy you're running, and never anything in your Downloads folder. If removing the other edition needs admin rights the installer doesn't have (e.g. a per-user install trying to remove a per-machine one), it simply skips that step and reports it — it never blocks or fails the install. This consolidation also runs on a silent self-update, so a routine nd300 update quietly leaves you with a single, current install. (Under the hood this is the hidden nd300 migrate-cleanup command, invoked by the installers; you never need to run it by hand.)

Cargo

cargo install nd300

Older installed copies that still request nd-300-installer.sh or nd-300-installer.ps1 are supported by compatibility aliases on every new GitHub release, so the legacy updater path can still reach the current installers.

Cargo itself cannot run ND300-specific uninstall hooks for unrelated old install locations. If an older installer-managed nd300 appears before Cargo's bin directory on your PATH, run nd300 update first, or run nd300 uninstall before cargo install nd300; the updater knows how to remove the old ND300 layout and complete the Cargo install.

From Source

git clone https://github.com/QubeTX/qube-network-diagnostics.git
cd qube-network-diagnostics
cargo build --release

Usage

nd300 — Network Diagnostic

As of v3.0.0, every action command is available either as a subcommand or as a flag — both forms are first-class and produce identical behavior. Pick whichever you prefer.

# Default user mode — clean summary
nd300

# Technician mode — full deep diagnostics
nd300 -t

# Change DNS configuration (interactive)
nd300 dns          # subcommand form (recommended); on success continues to diagnostics
nd300 -d           # legacy flag form (still supported); identical behavior

# Diagnostic-driven fix loop (subcommand form, recommended)
nd300 fix

# Same thing — legacy flag forms (still supported)
nd300 -f
nd300 --fix

# Auto-confirm medium-risk prompts (does NOT bypass high-risk Y/N)
nd300 fix --yes
nd300 -f -y

# Skip the speed test for faster execution
nd300 --fast
nd300 fix --fast

# JSON output for scripting
nd300 --json
nd300 fix --json    # JSON works after subcommands too (global flag)

# ASCII characters instead of Unicode
nd300 --ascii

# Disable colored output
nd300 --no-color

# Custom report title
nd300 -T "Office Network Check"

# Custom speed test duration per provider (seconds)
nd300 --speed-duration 20

# Self-update — both forms work
nd300 update
nd300 --update

# Reset DNS cache — both forms work
nd300 clear-dns
nd300 --clear-dns
nd300 -c

# Uninstall — both forms work
nd300 uninstall
nd300 --uninstall

# Show help
nd300 --help
nd300 fix --help    # subcommand-specific help

speedqx — Standalone Speed Test

# Full quad-provider speed test (Cloudflare + NDT7 + LibreSpeed + fast.com)
speedqx

# Custom duration per direction (30s download + 30s upload per provider)
speedqx --duration 60

# Override fast.com duration (defaults to "auto")
speedqx --fastcom-duration 30

# JSON output
speedqx --json

# Quick test with shorter duration
speedqx --duration 10 --latency-probes 5

Example Output

╔══════════════════════════════════════════════════════════════╗
║                   ND-300 Network Diagnostic                 ║
╠══════════════════════════════════════════════════════════════╣
║ Category         │ Status │ Details                         ║
╠══════════════════╪════════╪═════════════════════════════════╣
║ Network Adapters │  OK    │ Wi-Fi (connected)               ║
║ IP Configuration │  OK    │ 192.168.1.42/24                 ║
║ Default Gateway  │  OK    │ 192.168.1.1                     ║
║ DNS Resolution   │  OK    │ 1.1.1.1, 8.8.8.8               ║
║ Public IP        │  OK    │ 203.0.113.45 (Cloudflare)       ║
║ Latency          │  OK    │ 12ms avg (1.1.1.1)             ║
║ Speed Test       │  OK    │ ↓ 245 Mbps  ↑ 48 Mbps          ║
║ Port Check       │  OK    │ 8/8 reachable                   ║
╚══════════════════╧════════╧═════════════════════════════════╝

Command Line Options

Flag	Description
`-t, --tech`	Technician mode — show full technical report with deep diagnostics
`-T, --title <TITLE>`	Custom title for the report header
`--json`	Output results as JSON
`--ascii`	Use ASCII characters instead of Unicode box-drawing
`--no-color`	Disable colored output
`--fast`	Skip the speed test (faster execution)
`--speed-duration <SECS>`	Speed test duration in seconds (default: 10, min: 4)
`--verbose`	Show additional debug/trace information
`-d, --dns`	Change DNS servers and verify connectivity (requires elevated privileges)
`-f, --fix`	Run the diagnostic-driven triage / fix loop (requires elevated privileges). Equivalent to `nd300 fix`.
`-c, --clear-dns`	Flush the system DNS cache. Equivalent to `nd300 clear-dns`.
`--uninstall`	Remove nd300 from the system. Equivalent to `nd300 uninstall`.
`--update`	Check for updates and install the latest version. Equivalent to `nd300 update`.
`-y, --yes`	Auto-confirm medium-risk prompts when running the fix flow. Does not bypass high-risk Y/N.
`-h, --help`	Print help
`-v, --version`	Print version

Subcommands

Subcommand	Equivalent flag	Description
`nd300 dns`	`nd300 -d` / `nd300 --dns`	Change DNS servers and verify connectivity (semi-exit-early: exits on failure, continues to diagnostics on success)
`nd300 fix [-y]`	`nd300 -f` / `nd300 --fix`	Diagnostic-driven triage and recovery loop
`nd300 update`	`nd300 --update`	Self-update to the latest release
`nd300 clear-dns`	`nd300 -c` / `nd300 --clear-dns`	Flush the DNS cache and exit
`nd300 uninstall`	`nd300 --uninstall`	Uninstall nd300 from this system

SpeedQX Options

Flag	Description
`--json`	Output results as JSON
`--ascii`	Use ASCII characters instead of Unicode box-drawing
`--no-color`	Disable colored output
`--duration <VALUE>`	Test duration per direction for CF/NDT7/LS: seconds or "auto" (default: 30)
`--fastcom-duration <VALUE>`	Test duration per direction for fast.com: seconds or "auto" (default: auto)
`--latency-probes <N>`	Number of latency probes (default: 20)
`--update`	Check for updates and install the latest version
`-v, --version`	Print version
`-h, --help`	Print help

User Mode vs Technician Mode

User mode (default) runs 8 core diagnostics and presents a clean summary table. Ideal for quick network health checks.

Technician mode (-t) runs all 8 core diagnostics plus 18 additional deep diagnostic modules. Produces a detailed technical report with per-module breakdowns, suitable for troubleshooting and support workflows.

Diagnostics Covered

Core Diagnostics (both modes)

Network Adapters
IP Configuration / Interfaces
Default Gateway
DNS Resolution
Public IP
Latency
Speed Test (Cloudflare + M-Lab NDT7 in nd300; all 4 providers in SpeedQX)
Port Connectivity

Deep Diagnostics (technician mode only)

ARP Table
Routing Table
Active Connections
Listening Ports
DHCP Lease Info
Protocol Statistics
Adapter Hardware Details
Proxy Detection
VPN Detection
Firewall Status
DNS Cache
IPv6 Connectivity
MTU Discovery
Connection State Summary
Bufferbloat Detection
Reverse DNS
TLS Inspection
Traffic Counters

Fix Flow (`nd300 fix` / `nd300 -f`)

The fix flow runs a diagnostic-driven triage loop: it tests the network, looks at what actually failed, applies only the recovery actions that target those specific failures, re-tests, and repeats. Requires elevated privileges (sudo on macOS/Linux, Administrator on Windows).

A clean network completes nd300 fix in under 8 seconds and applies zero actions. Latency-only findings are reported as advisory because ICMP can be rate-limited or deprioritized by healthy networks. A real failure usually clears in 1–2 iterations.

How it works

1. Run baseline diagnostics
2. If everything passes → done.
3. Look at which specific diagnostics failed.
4. Group them by root cause (e.g. interface-down ⇒ skip DNS/gateway/IP — they cascade).
5. Pick the safest justified action that targets a remaining failure and apply it.
6. Wait for the system to stabilize.
7. Re-run the diagnostics.
8. Repeat until everything passes, or no further actions are available.

The loop is bounded by three independent caps so it always terminates:

≤ 6 iterations
≤ 4 minutes wall clock
Per-action attempt cap (typically 1 — failed actions are not retried)

Action ladder

Actions are tried by evidence and risk: cheap first, reversible first, and only when the current failure set justifies the action. DNS repair is intentionally staged so the tool flushes caches and restores router-provided DNS before considering a public DNS change.

Cost / risk	Action	Targets
Cheap / Low	Flush DNS cache	DNS
Cheap / Low	Reset DNS to router defaults	DNS
Cheap / Low	Switch DNS to Cloudflare 1.1.1.1	DNS, only after safer DNS-specific fixes fail
Cheap / Low	Flush ARP cache	Gateway
Medium / Low	Restart networking services	DNS, gateway, public IP
Medium / Low	Renew DHCP lease	Gateway, public IP, adapters, interfaces
Medium / Medium	Temporarily disable consumer VPNs	Public IP, DNS; interactive confirmation required
Expensive / Medium	Restart the network adapter	Adapters, interfaces, gateway, DNS, public IP
Expensive / High	Deep stack reset (Winsock / TCP-IP / IPv6 on Windows; recreate network service on macOS; recreate NetworkManager profile on Linux)	Last-resort recovery

Enterprise VPNs (Cisco AnyConnect, Zscaler, Palo Alto / GlobalProtect, F5, Check Point, Juniper) are never auto-disabled. Consumer VPN disable is also skipped in JSON or non-interactive mode, even with --yes, because the tool cannot safely guide re-enable/recovery steps there. Other medium-risk actions such as DHCP reset, service restart, adapter restart, and public-DNS changes are skipped in JSON or non-interactive mode unless --yes can safely auto-confirm the medium-risk prompt. High-risk actions are never auto-confirmed.

Confirmation prompts

Medium-risk actions explain what they will change and require confirmation unless --yes is provided. The deep stack reset is high-risk and is always gated behind a structured plain-language prompt:

┌─ Escalating: Reset Windows networking stack ──────────────────────────────
Why I want to do this:
  Gateway and DNS are still failing after DHCP renew and ARP flush.
  Resetting the networking stack rebuilds Windows' TCP/IP, Winsock,
  and IPv6 catalogs from scratch — the standard fix when simpler
  steps haven't recovered the connection.

What will happen:
  • You will lose internet for ~10–15 seconds.
  • Open VPN sessions and SSH connections will drop.
  • A reboot is recommended afterward; nd300 will remind you at the end.

Reversible: requires reboot to fully revert
Typical duration: 10–15 seconds

Continue? Type 'y' to proceed, anything else to skip:

--yes does not bypass high-risk prompts — they always require an explicit y. Anything else (including a blank Enter) is treated as N. In --json / non-interactive contexts, high-risk actions are skipped, not auto-applied, with a clear marker in the report.

Hard-block detection

Some failure shapes can't be auto-fixed. The loop short-circuits cleanly with guidance instead of thrashing:

No physical link — no cable / Wi-Fi.
ISP outage shape — local network healthy, public internet failing.
Enterprise VPN active — diagnostics shaped by a managed VPN we won't disable.

Fix Report

Every run produces a Markdown report at ~/Downloads/nd300-fix-report-YYYYMMDD-HHMMSS.md:

Verdict — Fixed, Partially fixed, Couldn't fix, Cannot fix from here, Timed out, or Stopped at your request.
Baseline diagnostics — full table snapshot before any action ran.
Iteration timeline — for each loop pass: which actions ran, captured stdout/stderr/exit/duration, and the diagnostic delta after.
Final diagnostics — same table as baseline so you can see what changed.
Environment — OS, version, elevation status, VPNs detected.
What to try next — concrete suggestions when the fix didn't fully succeed (restart router, contact ISP, check for driver updates, etc.).

In JSON mode (nd300 fix --json), the schema reports the same data as outcome, iterations, applied_actions[], remaining_failures[], hard_block, and report_path.

DNS Configuration (`nd300 dns`)

nd300 dns (or the legacy flag nd300 -d / --dns) provides a standalone way to change your DNS configuration. Requires elevated privileges. The subcommand and flag are identical: both are semi-exit-early — they exit on failure, and on success fall through to running standard diagnostics so you can immediately confirm the change improved connectivity.

Providers:

Cloudflare (recommended) — 1.1.1.1 (privacy-focused)
Google — 8.8.8.8 (reliability)
NextDNS — Encrypted DNS with filtering (requires config ID)
Automatic — Reset to system default (DHCP)
Hybrid (not recommended) — Cloudflare + Google

NextDNS encryption by platform:

Windows — DNS-over-HTTPS via netsh DoH template registration
Linux — DNS-over-TLS via systemd-resolved (falls back to plain IPs via nmcli)
macOS — NextDNS CLI client (nextdns install/activate), plain IPs if CLI not installed

After setting DNS, the tool verifies both DNS resolution and HTTP connectivity. If verification fails, it automatically reverts to DHCP and reports the result. On success, full diagnostics run to confirm network health.

Man Pages (Linux/macOS)

Man pages are generated at build time and included in release archives. To install after building from source:

sudo cp man/nd300.1 /usr/share/man/man1/
sudo cp man/speedqx.1 /usr/share/man/man1/
sudo mandb

Then use man nd300 or man speedqx to view documentation.

Building from Source

git clone https://github.com/QubeTX/qube-network-diagnostics.git
cd qube-network-diagnostics
cargo build --release

Binaries will be at target/release/nd300 and target/release/speedqx (or .exe on Windows).

Self-Update

Both binaries support self-updating to the latest release. Either form works:

nd300 update          # subcommand form (recommended)
nd300 --update        # legacy flag form (still supported)
speedqx update
speedqx --update

The updater runs a probe-and-retry chain so missing tools don't block the update:

Checks the latest release on GitHub. If you're already on it, exits 0 with no action.
Tries cargo install nd300 --force first when cargo --version succeeds on your system.
If Cargo succeeds while the currently running ND300 copy lives outside Cargo's bin directory, removes the old installer-managed nd300/speedqx layout so the new Cargo install is not shadowed on PATH.
If Cargo reports that an existing nd300 or speedqx binary is blocking installation, runs ND300's uninstall cleanup for the current install and retries cargo install nd300 --force.
After a successful cargo install, re-runs nd300 --version to confirm the new version actually landed. crates.io can briefly serve the old version right after a release (publish lag), or a different nd300 may be earlier on your PATH; if the running binary didn't change, the updater falls through to the prebuilt installer (which always carries the latest version) instead of looping "update available" forever.
If cargo isn't available (or still fails), falls through to the cargo-dist installer for your platform — curl | sh then wget | sh on macOS/Linux, powershell.exe then pwsh.exe on Windows. The installer URL uses GitHub's releases/latest redirect, so it always resolves to the newest release.
Whichever strategy succeeds first wins; the chain stops there.
If every strategy fails, both pretty and --json output show a per-attempt diagnostic block listing what was tried and why each failed, so you can fix the environment manually.

Windows installer-aware self-update

If you installed via one of the four first-class Windows installers (MSI/EXE × Global/Corporate — see Installation), nd300 update reads the HKCU\Software\ND300\InstallSource marker that installer wrote and downloads the matching installer for an in-place upgrade — rather than switching you to a different installer/format (which would leave duplicate Add/Remove Programs entries). If no marker is found, it falls back to detecting the install from the binary's path; cargo / PowerShell-installer users get the cargo-first chain above.

Before running a downloaded MSI/EXE, the updater fetches the asset's .sha256 sidecar and verifies the download against it (refuse-on-mismatch) — defending against a corrupted download or a network MITM (corporate TLS-interception proxies, hostile WiFi). After the installer exits, it re-runs --version to confirm the file replacement actually took effect (and surfaces the reboot-required case honestly if Windows scheduled a deferred replace).

Consolidation runs on a silent self-update too. The Windows installers re-run by nd300 update carry the same two clean-up options (remove an older Cargo copy, remove the other edition) — both default on, and the silent self-update path (msiexec /passive, Inno /SILENT) keeps them on, so a routine update leaves you with exactly one current install/edition. Anything that would need admin rights the update doesn't have is skipped and reported, never failing the update.

Versioning is prerelease-aware: a prerelease of an upcoming version is treated as newer than the previous stable patch, and a stable release is newer than its own prerelease. GitHub's unauthenticated rate-limit case (60 requests/hour per IP) is named explicitly so you know to just wait.

Current releases publish the canonical nd300-installer.sh and nd300-installer.ps1 assets plus legacy nd-300-installer.* aliases for older installed copies.

Update JSON output

In --json mode, the response includes "strategy" (the precise variant that ran or was attempted) and, on failure, an "attempts" array. The legacy "method" field still maps to "cargo" or "installer" for backward compatibility. On Windows, every update payload also carries a top-level "install_origin" field — one of msi-global, msi-corporate, exe-global, exe-corporate, cargo-or-installer, or unknown (the field is omitted on macOS/Linux, where install origin doesn't vary).

{
  "action": "update",
  "success": true,
  "current_version": "3.0.11",
  "latest_version": "3.1.0",
  "update_available": true,
  "method": "installer",
  "strategy": "msi_corporate",
  "install_origin": "msi-corporate"
}

The precise "strategy" values are cargo, installer_curl, installer_wget, installer_powershell, installer_pwsh, msi_global, msi_corporate, exe_global, and exe_corporate.

Speed Test Methodology

The speed test uses a technician-grade accuracy pipeline matching the SpeedQX web speed test:

Modified trimean (Ookla-style): (P10 + 8*P50 + P90) / 10 for robust central tendency
30% slow-start discard: eliminates TCP ramp-up contamination
IQR outlier filtering: removes transient congestion and measurement artifacts
Winsorized cross-validation: catches edge cases where IQR filtering is too aggressive
Upload-specific pipeline: keeps fastest 50% of post-warmup samples (following Speedtest.net methodology)
RFC 3550 jitter: exponentially weighted moving average, the standard used by VoIP and real-time media
Bounded inverse-variance weighted aggregation: combines every successful provider while preventing any single provider from dominating the result
Provider divergence detection: flags when the full provider spread differs by >30%, indicating possible throttling or QoS

For a full technical breakdown, see the SpeedQX Technical Report.

License

PolyForm Noncommercial 1.0.0

nd300 3.2.1