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