net/freeradius: Fallback authentication does not work

[Crazyachmed]

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Describe the bug My Access-Point is set to PSK+MAC-Authentication. A valid user works correctly, but an invalid user is rejected, but Fallback Authentication is activated. The log shows this:

via PAP: Mon Oct  6 18:09:20 2025 : Auth: (617) Login incorrect (No Auth-Type found: rejecting the user via Post-Auth-Type = Reject): [xxx/xxx] (from client ap4 port 1123 cli xxx)

via CHAP: Mon Oct  6 18:09:27 2025 : Auth: (618) Login incorrect (chap: &control:Cleartext-Password is required for authentication): [xxx/<via Auth-Type = CHAP>] (from client ap3 port 1123 cli xxx)

It does not matter if another valid user is configured. Trying around I can make it work when I remove the block

DEFAULT Framed-Protocol == PPP
        Framed-Protocol = PPP,
        Framed-Compression = Van-Jacobson-TCP-IP

from /usr/local/etc/raddb/users and send SIGHUP to radiusd - however I am unsure if that is the best solution.

I think my temporary solution will be to just remove that block from plugins/net/freeradius/src/opnsense/service/templates/OPNsense/Freeradius/users

Expected behavior Fallback authentication should accept unkown userse.

Additional context I have used the FreeRADIUS-plugin a couple of years ago, and the config was retained by OPNsense after the plugin was removed for a long time. Maybe this could also be related to some stale setting?

Environment Software version used and hardware type if relevant. e.g.:

OPNsense 25.7.4-amd64 freeradius-plugin 1.9.27_1