Network Tracker

A desktop tool (Kotlin + Swing/FlatLaf) that monitors your connection and works out where a problem is: this PC's link to the router, the router itself, the router's connection to your ISP, the wider Internet, DNS, or the remote host you're trying to reach.

Run

Requires a JDK (built and tested with Java 25). No admin rights needed.

./gradlew run

Or build a single runnable jar:

./gradlew fatJar
java --enable-native-access=ALL-UNNAMED -jar build/libs/network-tracker-1.0.0-all.jar

How it works

On start it auto-detects your default gateway (router), the ISP edge router (first router beyond your network that answers ping, found by traceroute), your DNS server, and uses 1.1.1.1 and 8.8.8.8 as Internet anchors. Add any IP or hostname in the toolbar to monitor it too.

Every round, all targets are probed at the same moment. That's the key to attribution:

The same comparison is applied to latency spikes, and the Events log attributes each outage and spike to where it started.

Features

• Dashboard: path health (PC → Router → ISP → Internet → DNS → Targets), live latency chart, loss/latency timeline (red that lines up vertically shows where a drop started), per-target statistics (loss, min/avg/max, jitter) and a plain-English diagnosis with suggested fixes.
• Traceroute: continuous MTR-style trace with per-hop loss/latency and automatic analysis that ignores harmless ICMP rate-limiting at intermediate hops.
• Events: outages, recoveries, latency spikes, Wi-Fi roaming and weak-signal warnings.
• Network Info: adapter, gateway, DNS, and Wi-Fi details (signal, band, channel, link rate) with signal history.
• Traffic: see what's happening on your network.
  • Packets: live packet list with a plain-English explanation of each packet, a full field-by-field decode (Ethernet, ARP, IPv4/6, ICMP, TCP, UDP, DNS/mDNS/LLMNR, DHCP, TLS with site names, QUIC, HTTP, SSDP, NTP, STUN, NetBIOS, LLDP…) and a hex view that highlights the selected field. TCP analysis flags retransmissions, lost segments, duplicate ACKs, resets and zero windows.
  • Conversations, Applications (traffic per program), Devices (what's on your LAN), Protocols (hierarchy breakdown), and Connections (every open socket and its program).
  • Filter with plain words or proto:dns app:chrome host:google port:443 dir:out len>1000 problems, right-click anything to filter by it, follow a stream, and open/save .pcap files for Wireshark.
  • Packet capture needs Npcap on Windows (free; install with default options). Connections, bandwidth and opening capture files work without it.
• Export: text diagnostic report (to send to your ISP) and raw CSV of every measurement.
• Light/dark theme; settings and custom targets are remembered.

On Windows, pings use the native ICMP API (via JNA) for precise timing and TTL control. Other platforms fall back to the system ping command. DNS is tested with raw queries sent straight to the server, which bypasses the OS cache.

Privacy

Everything stays on your machine. The app sends no telemetry, and only contacts the hosts it monitors (your router, ISP edge, DNS server, 1.1.1.1, 8.8.8.8 and targets you add); the Traffic tab also does reverse-DNS lookups to show host names. Exported reports, CSVs and especially saved .pcap captures contain your network details and traffic, so review them before sharing.

License

MIT