NetDiag+ Network Toolkit

NetDiag

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About this app

Your video call froze. Your game just spiked to 300 ms. Your Wi-Fi says "Excellent" and the speed test looks fine. NetDiag+ tells you what's actually wrong — and where, in the chain from your phone to the server, the problem lives.

27 pro network tools on stock Android. No root, no NDK, no accounts.

MEASURE
• Ping (real ICMP, no fake TCP fallback)
• Path MTU (DF-bit binary search — find fragmentation)
• Traceroute + MTR (per-hop loss and latency)
• Speed Test (Cloudflare, with jitter — not just Mbps)
• STUN / NAT type (spot symmetric NAT that breaks P2P)
• Wi-Fi info (signal, channel, 2.4 GHz overlap warning)

INSPECT
• DNS lookup + Encrypted DNS (DoH; compares 3 resolvers)
• Reverse DNS, WHOIS (with IANA referral)
• TLS Inspector (full cert chain, expiry)
• SSL Checker (probes TLS 1.0-1.3 separately)
• HTTP/3 + QUIC reachability
• HTTP headers + redirect chain

SCAN
• LAN Scanner (concurrent /24 sweep)
• Port Scanner (19 common ports)
• TCP Ping (when ICMP is filtered)
• mDNS / Bonjour browse

DIAGNOSE
• Network Passport (one-tap composite report — shareable)
• Site Reach (DNS → TCP → TLS → HTTP; names the failing layer)
• VPN Check (should you use a VPN on this network? IP + NAT + DNS leak + geo — 4 probes, one answer)
• Host Monitor (watch a service for outages)
• Subnet Calculator (offline)
• IP Info (geolocation, ISP, AS; flags mobile/proxy/hosting)
• Network Info (transport, DNS, MTU)
• History (on-device, 100 entries)

BUILT TO BE TRUSTED
• No account, no sign-up
• Everything runs on your device — nothing sent to our servers
• Firebase Analytics is optional and captures no personal data
• Test history stays local
• Open protocols only (ICMP, TCP, UDP, HTTPS, DoH) — no proprietary telemetry

WHO IT'S FOR
• Gamers chasing the lag spike that ruins ranked matches
• Remote workers whose Zoom freezes while the speed test says fine
• Anyone who wants to check that their ISP delivers what they pay for
• Network engineers, SREs, home-lab tinkerers who want real numbers

Support: netdiag.online/support/
Privacy: netdiag.online/privacy/

What’s new

• Health Score: one number for your connection, and who is to blame — Wi-Fi, router or provider. One run of about 40 seconds; tap any row to see how the points add up.
• More accurate Bufferbloat grading: the download phase now loads the line fully, and the test also reports your download and upload speed.
• Also: export any result as text or PDF, BGP Info and IPv6 Check, continuous MTR, and Ping with up to 10,000 packets at intervals down to 0.05 s.