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Networking

What is RADIUS?

Definition

RADIUS, or Remote Authentication Dial-In User Service, is a standard protocol that lets network equipment ask a central server whether a user should be allowed on, what limits to apply, and to report how much they used. It provides authentication, authorisation and accounting for wireless networks, and underpins most enterprise guest access.

The three A's in plain terms

Authentication answers "is this who they claim to be": the access point forwards credentials to the RADIUS server rather than deciding locally. Authorisation answers "what are they allowed to do": the server's reply can carry attributes such as a session timeout, a bandwidth cap, or a VLAN to place the device in. Accounting answers "what did they use": the access point sends start, interim and stop records describing session duration and data volume. That accounting stream is what makes per-session reporting and time-limited access possible.

Why guest WiFi platforms care about it

RADIUS is the common language nearly every vendor speaks. Because it is a standard, a portal that authorises sessions over RADIUS can work with a wide range of hardware without a vendor-specific integration for each. It also enables features that a simple portal cannot deliver alone: mid-session policy changes via Change of Authorisation, hard session time limits enforced by the network rather than the browser, and per-user bandwidth shaping. VoqadoWiFi does not use RADIUS: it runs as the external portal for TP-Link Omada and Ubiquiti UniFi and authorises each guest through the controller itself.

Operational cautions

RADIUS is a single point of dependency: if the server is unreachable, new guests cannot authenticate, so plan for redundancy or a graceful fallback. The original protocol has weak transport security, so run it inside a trusted network or over an encrypted tunnel, and use long random shared secrets that differ per network device. Accounting records can accumulate quickly in a busy venue, so decide on a retention period up front and align it with your privacy policy rather than keeping session logs indefinitely by accident.

Run a guest WiFi login on your own network

VoqadoWiFi runs branded guest portals on TP-Link Omada and Ubiquiti UniFi networks. The Starter plan is free forever: one location, 500 logins a month, consent logging included.

Common questions about radius

Do I need a RADIUS server to run guest WiFi?

Not always. Many small venues run an external captive portal that authorises sessions through the controller's own API without a separate RADIUS server. That is how VoqadoWiFi works with Omada and UniFi. RADIUS becomes valuable when you need standardised accounting, enforced session limits, or one authentication source across mixed hardware.

What is Change of Authorisation?

It is a RADIUS extension that lets the server push a policy change to an active session, for example disconnecting a device or moving it to a different bandwidth tier, without waiting for the guest to reconnect.

Related terms

RADIUS rarely comes up on its own. These are the entries operators usually read next.