After a successful walk, Results Authorization is configured with
the Results Authorization Options group on the Search
Settings page. The primary setting is Authorization Method
(here), which is determined by the
authentication system(s) in use by the indexed URLs. If cookie-based,
this is set to Forward login cookies; for all other systems,
it is set to Basic/NTLM/file - Prompt via form. Most of
the remaining settings depend on which method was selected; see
the Authorization Method setting (here)
for details.
There are also a few resource/tuning settings, such as Max Docs
to Auth-Check, Successful Auth Result Limit, Total Auth
Timeout, and Debug Results Authorization, which are not
required, but merely fine-tune the results.