Wi-Fi & Network Troubleshooting

You are diagnosing a wireless or LAN problem. Scoping is the first diagnostic act;
everything — including who works the ticket — follows from it. Infrastructure changes are
recommendations for the network owner, not edits you make.

Climb the Troubleshooting Ladder base skill first: past tickets for this client's network
(recurring drops at the same place or time are a pattern, not today's instance), then the
client's documentation — AP vendor and controller, SSID design, DHCP scopes and their server,
ISP and circuit.

Then ladder the scope; this is the diagnosis. Is it one device, everyone near one AP, one SSID
everywhere, or the whole site including wired? Whole-site is an incident — flag it
immediately: a site-wide outage worked as a single-user ticket wastes the response window.
Get numbers first: signal strength, which AP and band, IP config (valid
lease versus self-assigned 169.254), controller and AP status, DHCP scope utilization, ISP
circuit state.

Branch:

a. Single device — NIC driver version (verify current on the web), power saving, a stale
   saved profile (forget and rejoin), or a device pinned to congested 2.4GHz. Working elsewhere
   on the same SSID means positional — go to b.
b. Roaming — the device clings to a distant AP and drops when moving. Check minimum-RSSI and
   roaming settings on the infrastructure, and roaming aggressiveness on the NIC. Route
   controller changes to the owner with the evidence: which APs, which readings.
c. AP-wide — everyone near one AP. Check its status (up, recently rebooted, flapping uplink),
   channel utilization and interference, and any recent channel or power change. No settings
   tweak fixes RF physics: physical causes (new equipment, moved furniture, neighbour networks)
   make a site survey the honest next step.
d. DHCP exhaustion — devices connect but get no valid IP, or "connected, no internet" at peak.
   Compare scope utilization and lease time against device turnover; guest networks with long
   leases exhaust silently. Shorter leases or a wider scope is the owner's change, with the
   numbers attached.
e. Captive portal — it never appears (DNS interception versus HTTPS), a certificate error on it, or the auth backend is down. Separate "broken for all guests" from one device's portal
   detection: toggle Wi-Fi, try an http:// site.
f. Site-wide — wired affected too points at the ISP circuit, the edge firewall or router, or
   the core switch. Verify the demarc: can the edge device reach its gateway? If the ISP is down,
   only the ISP can act — log the outage reference and set an honest ETR.

Never guess channel plans, scope sizes or ISP details; take them from documentation or ask.
Verify from the affected location, not a green dashboard, then leave a plain-text
internal note (apply the PSA Note Discipline base skill): scope, branch, evidence, action or
handoff, verification.