Free Software Collection
Free Network Analysis and Packet Capture Tools
When a network misbehaves there is wide grey territory between "online" and "offline": pages load but one app spins, a machine on the LAN is unreachable, a smart home device sends something out at three in the morning. Guessing does not resolve it; the packets have to be laid out and read. These tools make the network visible. The list sorts by layer — link-level capture, host and port discovery, application-level requests, and joining your own devices into a private network.
7 curated recommendations
Selection Criteria
- Entirely free, with no pricing by interface count, capture duration or feature module.
- Runs locally and uploads nothing it captures.
- No account and no licence file required.
- Open source or with a public mechanism, so what it does can be audited.
Recommended Tools
Wireshark
Lays out every packet on the wire for you to read
- Open Source
- No Ads
- No Tracking
- Offline
Nmap
See what is actually on your network and which ports are open
- Open Source
- No Ads
- No Tracking
- Offline
mitmproxy
See exactly what requests an app or page is really making
- Open Source
- No Ads
- No Tracking
- Offline
Tailscale
Wires all your devices into one private network — no router config
- Open Source
- No Ads
- Cross-platform
- Self-hostable
WireGuard
A modern encrypted tunnel protocol configured in a dozen lines
- Open Source
- No Ads
- No Tracking
- Offline
Angry IP Scanner
Enter an IP range, press Start, and get a table of everything on the network
- Open Source
- No Ads
- No Tracking
- Offline
Trippy
Traceroute and ping in one, showing live which hop is dropping packets
- Open Source
- No Ads
- No Tracking
- No Sign-up
FAQ
- How do I see what is actually crossing the network?
- Wireshark. It lays out every packet passing the interface, dissecting protocols down to individual fields, and its filter expressions pull the few packets you want out of hundreds of thousands. TCP retransmissions, failed DNS resolution, a TLS handshake dying at a particular step — this is what locates them. The learning curve is not gentle, but neither is the ceiling of network troubleshooting.
- What is Nmap for?
- Discovering which devices are on a network, which ports they have open and what services are running. After filling a home with smart devices, a scan routinely turns up something unexpected — a camera with an unauthenticated web port, a machine with its database port open to the whole LAN. Scan only your own network; scanning someone else's is illegal in many places.
- Can HTTPS content be inspected?
- With mitmproxy acting as a man in the middle, yes. It sits between device and server and re-encrypts with its own certificate, making requests readable, editable and replayable. That requires installing and trusting its certificate on the device, which also means the capability applies only to devices you control. It is how you debug your own mobile app or find what a third-party SDK reports. Recent Android versions restrict ordinary apps from trusting user certificates, which is worth knowing.
- How do Tailscale and WireGuard relate?
- Tailscale runs on WireGuard underneath. WireGuard is the protocol and kernel implementation, configured in a dozen lines, but key distribution, address allocation and NAT traversal are yours to solve. Tailscale adds a control plane on top so devices join the network and punch through NAT after signing in, making a NAS at home reachable from outside as if it were on the local network. Take WireGuard for complete control, Tailscale to have it working immediately.