Network troubleshooting: from ping that doesn't work to nmcli

“Connected to Wi-Fi but the internet isn’t working.” Classic situation. Here’s my diagnostic sequence — and a reference for all the networking commands I use frequently.

Diagnostic sequence

1. Check the obvious suspects

• VPN with kill switch enabled? Disable it and test.
• Wi-Fi turned off by the laptop’s physical shortcut? On Dell it’s Fn+PrtScrn.

2. Check the network interface status

# list all interfaces
ip link

# see the status of a specific interface
ip link show wlp3s0

If the interface has status DOWN:

sudo ip link set wlp3s0 up

3. Check for rfkill block

rfkill controls “soft blocks” — disabling by software or keyboard shortcut:

sudo rfkill list all

If Soft blocked: yes appears, Wi-Fi was disabled by the keyboard shortcut. Fn+PrtScrn on Dell toggles it.

4. Restart network services

sudo systemctl restart NetworkManager
sudo systemctl restart dhcpcd
sudo systemctl restart systemd-resolved

Connectivity tests

# check dnsmasq configuration
dnsmasq --test

# see all network routes and gateways
ip route show

# list all local hosts (/etc/hosts)
getent hosts

# trace the path to a server
traceroute google.com

# domain info
whois lucio.app

Managing Wi-Fi with nmcli

nmcli is the terminal client for NetworkManager — more robust than dealing with services directly:

# list available networks
nmcli device wifi list

# list network devices
nmcli device show

# see saved connections
nmcli connection

# connect to a network
nmcli device wifi connect network_name

Quick interface reference

On my Dell, the interfaces have these names:

Interface	Type	Module
wlp3s0	Internal Wi-Fi card	ath10k_pci
wlp0s20f0u4	Bluetooth/USB adapter	rtl8192

Names vary by machine — ip link always reveals the correct ones.

Listing installed Wi-Fi drivers

inxi -Nazy
iwconfig

inxi -Nazy gives a nice summary of network devices and drivers. iwconfig shows wireless interface information in the old-style format (still useful).