How to Set Up a Captive Portal for Wi-Fi (Step-by-Step)

A captive portal is the login page a guest sees before their device gets internet access. For Wi-Fi businesses — hotels, cafés, schools and neighborhood ISPs — it is also the place where access becomes a product you can sell. This guide explains how a captive portal actually works and the steps to set one up without building the backend yourself.

How a captive portal works

When a device connects to your network, the router intercepts web traffic and redirects the browser to a portal page. Until the visitor authenticates — logs in, buys a plan, or redeems a voucher — the network keeps them off the open internet. Once access rules are satisfied, the router lets the device online.

Two components do the work: the captive portal page itself (what the customer sees and interacts with) and the access controller (the edge device that enforces the decision). With Authnet, the portal is hosted on your branded subdomain and the router enforces access using RADIUS.

What you need before you start

• A router or access point that supports captive portal mode and RADIUS authentication
• A way to host the portal page — a hosted captive portal platform removes this entirely
• Plans or vouchers to sell, with clear rules for quota, duration and device limits
• A payment flow if you plan to charge for access

Step-by-step setup with Authnet

1. Register your business

Create your business in the admin portal and reserve your name. Your name becomes the portal subdomain — for example yourbusiness.authnetworks.com — and the tenant portal goes live once the business is activated.

2. Define your access packages

Build subscription plans and voucher codes with your own price, data quota, duration and maximum devices. Time-based and volume-based plans are both supported, and the rules are enforced automatically at the edge.

3. Connect your router as a NAS device

In the dashboard, run the Add NAS Device flow. Configure your router security as WPA/WPA2-Enterprise, point the RADIUS server at api.authnetworks.com, set the RADIUS port and secret as shown in the onboarding dialog, then save. The dashboard will show the router online.

4. Test the flow

Connect a test device to the network. It should be redirected to your branded portal, where you can sign in, purchase a plan or redeem a voucher, and get online automatically once access rules are met.

Common captive portal mistakes to avoid

• Sharing one password with every guest — you lose monetization and control
• Skipping device limits, so one subscription serves a whole room
• Forgetting expiry rules, leaving access open after the purchase window
• Building the portal backend yourself when a hosted captive portal handles it

A good captive portal setup pays for itself the first time a guest buys a daily plan or redeems a voucher. Start with one coverage area, confirm the flow, then scale.