📡 Networking & Diagnostics

Free and open-source tools to find out what is happening on a network: capture and read packets, scan devices, measure speed, follow the route of a connection and run your own router or firewall. See also my note Computer Networks.

Open in the interactive Digital Resources

Wireshark
wireshark.org
The best-known packet analyzer. Captures network traffic and shows every protocol layer in readable form. Hard at first, irreplaceable later.
- #OPEN-SOURCE
- #PACKETS
- #ANALYSIS
- #PROTOCOLS
Nmap
nmap.org
Network scanner: which devices are on the network and which ports and services are open. Comes with Zenmap, a graphical interface. Scan only networks that are yours.
- #OPEN-SOURCE
- #SCANNER
- #PORTS
- #SECURITY
Angry IP Scanner
angryip.org
A simple, fast scanner that lists all devices in an IP range with their names. Good for finding that one device that got a new address.
- #OPEN-SOURCE
- #SCANNER
- #SIMPLE
- #CROSS-PLATFORM
iperf3
software.es.net
Measures the real speed between two computers in the network – the honest way to test Wi-Fi, cables and switches.
- #OPEN-SOURCE
- #SPEED
- #CLI
- #TESTING
MTR
bitwizard.nl
Combines ping and traceroute: shows every hop to a server and where packets are lost or delayed.
- #OPEN-SOURCE
- #TRACEROUTE
- #CLI
- #DIAGNOSTICS
OpenWrt
openwrt.org
A Linux system for routers. Replaces the manufacturer's firmware, gets security updates for years and adds VPN, VLAN and ad blocking.
- #OPEN-SOURCE
- #ROUTER
- #FIRMWARE
- #LINUX
OPNsense
opnsense.org
A firewall and router system for an old PC or a small box with two network ports. Web interface, VPN, intrusion detection and regular updates.
- #OPEN-SOURCE
- #FIREWALL
- #ROUTER
- #FREEBSD
GNS3
gns3.com
Builds virtual networks with real router and switch images and virtual machines – practise without breaking the home network.
- #OPEN-SOURCE
- #SIMULATION
- #LEARNING
- #LAB