+.B radius_authtypes
+A comma separated list of supported RADIUS authentication methods
+("pap" or "chap"), in order of preference (default "pap").
+.TP
+.B radius_dae_port
+Port for DAE RADIUS (Packet of Death/Disconnect, Change of Authorization)
+requests (default: 3799).
+.TP
+.BR radius_bind_min ", " radius_bind_max
+Define a port range in which to bind sockets used to send and receive
+RADIUS packets. Must be at least RADIUS_FDS (64) wide. Simplifies
+firewalling of RADIUS ports (default: dynamically assigned).
+.TP
+.B allow_duplicate_users
+Allow multiple logins with the same username. If false (the default),
+any prior session with the same username will be dropped when a new
+session is established.
+.TP
+.B guest_account
+Allow multiple logins matching this specific username.
+.TP