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Linux Networking Field Reference (10-Page Printable Cheat-Sheet)
Ten printable pages of Linux networking commands, flags and real lab output, including a ten-symptom troubleshooting decision tree. Free for members.
Troubleshooting
Broken networks, reproduced on purpose. Articles tagged Troubleshooting walk a fault from symptom to root cause using show commands, captures and a repeatable method.
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Top Linux Networking Commands: The 2026 Field Reference
Every Linux networking command that matters, grouped by the question it answers, with real captures from a four-hop lab and the triage order to run them in.
/proc/net and Networking sysctls: Where the Numbers Come From
Every Linux networking tool is a formatter over a handful of kernel files. Here is what is in them, how to read the hex, and what happens when you change the sysctls that matter.
iftop, nload, bmon, vnstat, nethogs Compared
Five live bandwidth monitors pointed at the same flow at the same time, with real terminal frames and a reconciliation of why they all report different numbers.
ngrep: grep for Network Traffic
Pattern matching against live packet payloads. The syntax, the hex mode, the file interop, and a real capture showing the server name leaking out of an encrypted session.
tshark: Wireshark in the Terminal
Wireshark’s full dissector library driven from an SSH session: capture filters against display filters, custom field output, ring buffers and the statistics taps that make triage fast.
socat: Port Forwarding and Bidirectional Relays
One command joins any two endpoints: TCP, UDP, TLS, UNIX sockets, serial ports or a program. Port forwards, TLS wrappers and protocol bridges from real captures.
netcat: Port Checks, File Transfers, Listeners
Open, refused, timed out and no route to host are four different tickets. Plus banner grabs, file transfer with no server, and why UDP tests lie.
curl for Network Engineers: Ports, HTTP, APIs
Prove a port is open, split DNS from TCP from server think time, test a device API and read a TLS failure, all with real output from a routed lab.
How Linux Resolves Names: resolv.conf, systemd-resolved, nsswitch
dig tests a nameserver. getent tests name resolution. The full path from nsswitch.conf to the wire, with the resolver deliberately broken and fixed.
host: The Fastest DNS Lookup Tool
One name in, one line out, and the only exit status of the three you can trust. Plus the timing test that complicates the fastest claim.
nslookup: Quick DNS Queries That Still Matter
Declared deprecated for twenty years and still on every machine. What it does well, where it will mislead you, and the debug flag nobody uses.