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FortiKoala
Staff
Staff
Oct 1, 2018 11:19 AM UTC

Technical Tip: Enable Captive Network Assistant (CNA)

  • Apr 16, 2026 1:17 PM UTC
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Description
Enabling the Captive Network Assistant (CNA) automatically opens a browser for authentication when a device is isolated. Upon connecting to the network, users will be notified that they are in a Captive Network and must visit the NAC portal to authenticate.

There are different captive portal detection solutions depending upon the operating system:  
Microsoft and Android - Captive Portal Detection (uses full browser)
iOS and macOS - Captive Network Assistant (CNA) (uses mini browser)

Scope
Versions 8.2.x and higher.
Solution
For configuration instructions, refer to the Captive Network Assistant reference manual in the Fortinet Document Library.

Note the following:
  • When enabled, this feature is enabled for all portals.  It cannot be enabled on a per portal basis.
  • This feature should not be used when using Endpoint Compliance Policies for MAC computers.  Since macOS launches a mini browser, users cannot download items, such as the agent, from within the Captive Network Assistant.
  • Domains used to determine whether or not to launch the browser will differ.  In addition, the end user experience can vary between vendor and operating systems. 

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