Duo Two-Factor Authentication for Barracuda SSL VPN with RADIUS and Duo Prompt

The iframe-based traditional Duo Prompt in Barracuda RADIUS configurations reached its end of support on March 30, 2024. Customers must migrate to a supported Duo Single Sign-On application with Universal Prompt or a RADIUS configuration without the iframe for continued support from Duo.

We recommend you deploy Duo Single Sign-On with a generic SAML application to protect Barracuda SSL VPN with Duo Single Sign-On, our cloud-hosted identity provider featuring Duo Central and the Duo Universal Prompt.

Another alternative is to reconfigure your existing radius_server_iframe Duo Authentication Proxy application so that it does not use the iframe, for example, RADIUS with Automatic Push for Barracuda SSL VPN.

Learn more about options for out-of-scope applications in the Universal Prompt update guide, and review the Duo End of Sale, Last Date of Support, and End of Life Policy.

The instructions for this solution were removed on April 2, 2025. Customers who had this configuration deployed before then and need to refer to the original instructions may contact Duo Support.