UniFi · Guest Wi-Fi · Captive portal

Guest Wi-Fi with a captive portal — built in layers, verified by tests

First published 20 October 2026 · From Ubiquiti's Hotspots & Captive Portals, Guest WiFi Best Practices, Isolation, and Zone-Based Firewall documentation, read in full. Items resting on Ubiquiti's legacy Controller Guide or versioned third-party walkthroughs are marked where used.

Do not fix the wrong thing first. “Guest Wi-Fi” is three separate layers owners constantly conflate: (1) a guest network, (2) a portal (the splash page — hospitality, not security), and (3) isolation (the actual security). A beautiful portal on an un-isolated network is a welcome mat on an open door. Build all three; verify the third with tests, not toggles.

The architecture, in Ubiquiti's model

When a guest joins, UniFi tags the device GUEST, authorized: false. Any web attempt redirects to the portal; completing it records authorization for that device (with an expiry) and the gate opens — to exactly the destinations your post-authorization rules allow. Before authorization, the guest lives in a walled garden: the portal itself plus any pre-authorization addresses you deliberately list. Two enablement scopes exist and are routinely confused: the portal per-SSID (Settings → WiFi → Hotspot Portal) and the Hotspot firewall zone per-network (Zone-Based Firewalls, Network 9.0+) — which also portals wired clients on that network.

The portal menu — as currently documented

MethodDocumented notes
VouchersCustomisable expiration, bandwidth limits, data quotas; generated/printed/revoked in Hotspot Manager — the small-business default.
PasswordOne shared password at the portal — simple; rotation is your hygiene problem.
PaymentStripe is the currently supported processor. (Legacy docs describe PayPal and others — retired; don't design around them.)
FacebookListed first in the current article. Its longevity depends on Meta's side — dress-rehearse it end-to-end before depending on it.
RADIUS / External Portal ServerAdvanced paths (your own auth/portal infrastructure).
None selectedThe click-through flow, with terms-of-use acceptance where you enable it (a documented portal element: guests can be required to accept your terms).

The setup ladder

  1. Guest network first: a separate network/VLAN for guests (your gateway routes it; the isolation steps assume this).
  2. Guest WLAN on that network, named obviously (“CafeName Guest”).
  3. Isolation layer (next section) — before any guest touches it.
  4. Rate limits: apply a bandwidth profile to the guest WLAN so one guest's cloud backup can't eat the till's card reader bandwidth (QoS/traffic-shaping is a documented UniFi facility; per-guest voucher quotas stack on top).
  5. Enable the portal (per-SSID or Hotspot zone — pick one scope deliberately), choose method(s), set the terms text if you use acceptance.
  6. Brand it: logo/background within the documented customisation; keep the page light — it loads pre-authorization, through the walled garden, on a stranger's phone.
  7. Vouchers (if chosen): generate the first batch in Hotspot Manager.
  8. Dress rehearsal with your own phone (next sections), then open the doors.

Isolation — three features, three scopes, one famous gap

FeatureScopeWhat it actually blocks
Network Isolation (or Hotspot zone defaults)Network-wideGuests initiating to internal networks: the zone matrix gives Hotspot→Internal Allow Return Traffic only, Hotspot→Hotspot and Hotspot→DMZ Block All — but Hotspot→Gateway is policy-dependent. Your gateway's admin page is a test, not an assumption.
Client Device IsolationPer-APGuest-to-guest within one access point. The gap: guests on different APs remain visible to each other through it.
Device Isolation (ACL)Switch levelCloses the cross-AP guest-to-guest path — requires the network be routed by a UniFi gateway or L3 switch.
Proxy ARPPer-WLANCongestion hygiene Ubiquiti recommends for busy guest networks — not a security boundary; don't list it as one.

Verify like an auditor — the 8 tests (from a guest device, unauthorised then authorised)

  1. Reach the portal (pre-auth) — and nothing else on the internet.
  2. Reach a pre-authorization-listed address only if you listed one deliberately.
  3. After authorising: browse the open internet.
  4. Ping/browse the LAN printer → must fail.
  5. The NAS / POS / office PC → must fail.
  6. Another guest's device (same AP, then a different AP) → must fail both times (test 7 is where the famous gap shows itself).
  7. The gateway's admin UI → must fail (the policy-dependent one).
  8. A wired device on the guest network → portal + same isolation, if you used the zone scope.

Voucher operations (Hotspot Manager)

Single-use vouchers die after first authorisation; multi-use serve a group/event. Each carries its duration and optional byte quota and bandwidth limits. Day-to-day verbs are documented: Print / Print Batch / Print All Unused, Revoke (“immediately deactivate”), and guest Extend (+24 hours per action). Staffing pattern: Operator Accounts — admin-created, restricted to Hotspot Manager only, documented as designed for hotel-style front desks. That is exactly a café counter: staff can mint and revoke vouchers and cannot touch your network settings. (These functions are documented in Ubiquiti's Controller Guide; exact menu paths shift between Network versions — the capabilities are the stable part.)

Portal realities — the honest section

FAQ

Portal or just a password on the SSID?

Different jobs: the SSID password controls joining; the portal controls authorization after joining (terms, vouchers, expiry, per-device records). Many cafés need only a guest network + isolation + the password on the receipt; the portal earns its complexity when you want vouchers, branding, or acceptance records.

Guests say “Wi-Fi connected, no internet, no page.”

The dress-rehearsal failures, live: portal detection defeated (VPN/private DNS), a certificate-alarming secure portal, or the guest joined before you finished enabling. Re-run the 8 tests; the failing test names the layer.

Can staff get longer access than guests?

Keep staff off the guest network entirely — a separate staff WLAN on the internal network (see our Wi-Fi guides). Mixing staff into the guest system for convenience quietly re-opens the door the isolation tests just closed.

Sources

Ubiquiti Help Center — UniFi Hotspots and Captive Portals (method inventory, scopes, state model via the External Hotspot API article), Best Practices: Guest WiFi, Implementing Network and Client Isolation, Zone-Based Firewalls (Hotspot matrix), QoS and Traffic Shaping · Ubiquiti Controller User Guide (legacy; voucher/Hotspot Manager operations, secure-portal certificate warning — tiered as legacy).

Verification note: the method inventory, isolation scopes and zone matrix were confirmed from Ubiquiti's current articles on 20 October 2026. Default session expiry (reported as 8 hours) rests on consistent third-party UI walkthroughs rather than a current help article and is treated as a setting to confirm on your console, not a fact.