Freeradius the custom module to set Framed-IP-Address

Rest doesn't set the Auth-Type, you have to do it manually.

authorize {
    rest
    if (ok) {
        update control {
            Auth-Type := rest
        }
    }
}

authenticate {
    rest
}

Auth-Types are automatically created for modules listed in authenticate (you don't actually need the Auth-Type stanza).

You don't need to call rest in authorize if you don't need to, something like this would also work fine:

authorize {
    if (User-Password) {
        update control {
            Auth-Type := rest
        }
    }
}

Edit:

Note: Prior to version 3.0.4 the REST module used control:Cleartext-Password to get the user's password, so in order for the module to work you'd need to copy the value over from request:User-Password:

authorize {
    if (User-Password) {
        update control {
            Cleartext-Password := &User-Password
            Auth-Type := rest
        }
    }
}

Versions 3.0.4 and later look for request:User-Password instead, which should just work in most cases.

rest.authorize {
    fail = 1
}
if (reject || fail) {
    update reply {
        DHCP-Message-Type = DHCP-NAK
    }
}

OK. So you have four options:

• Return a 401 with a JSON content-type and just a set of empty braces {} (that may work)
• Use the v3.0.x HEAD commit where i've just altered the behaviour to allow empty bodies. It's odd it's actually calling the body data callback for an empty body. I didn't expect that, which is why it errors out. This will appear in released version 3.0.4.
• Edit the return statement just below RDEBUG2("Skipping....") in src/modules/rlm_rest/rest.c to be return 0.
• Edit your rest call to match the snippet I added above (because putting it after this bulleted list screwed with the formatting).