How it works
A device needs the right settings and a usable signal before anything else works. Wireless adds distance, interference, and band selection to the list of things that can go wrong.
Confirm the device has an address and a route out before investigating anything further up. Many application failures are simply connection failures wearing a disguise.
Common error
A full signal bar does not prove a working connection. A device can be associated with an access point and still have no path to anything beyond it.
Worked example
A device associates with Wi-Fi and reaches a local printer but cannot reach a remote service. Read its settings.
Evidence
Address: 10.20.1.25
Mask: 255.255.255.0
Gateway: not configured
Local printer: 10.20.1.40The local printer is on the same /24 subnet, so the device can reach it without routing through a default gateway. A missing gateway explains the lack of a route to remote networks. Configure the approved gateway and verify a remote destination; do not infer full internet access from association alone.
Exercises
1.3.1
A client at 10.20.1.25/24 reaches 10.20.1.40 but not 10.20.2.40. What additional network function is needed?
Show solution
It needs routing through a reachable gateway, together with an allowed route and return path between the subnets. The different /24 networks cannot communicate merely because both addresses start with 10.20.
1.3.2
List three checks after reconnecting a laptop to Wi-Fi.
Show solution
Confirm association with the intended network, inspect the address/mask/gateway/DNS settings, and test a required service. Use tests appropriate to the service instead of treating signal bars as proof of connectivity.