If this optional parameter is set, AuthBy EXTERNAL will
                  determine the type of the reply from the first line of the stdout output
                  of the external program, rather than the exit code of the external
                  program.
               The following codes are recognised:
               
                  - ACCEPT
                     
Reply with an Access-Accept
                   
                  - REJECT
                     
Reply with an Access-Reject
                   
                  - IGNORE
                     
Do not reply
                   
                  - CHALLENGE
                     
Reply with an Access-Challenge
                   
                  - REJECT_IMMEDIATE
                     
Reply with an Access-Reject, and do not
                        consider any other DEFAULT users in a chained Auth-Type
                        request