/etc/security/pam_duo.conf is in libpam-duo 1.9.6-1.
This file is owned by root:root, with mode 0o600.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 | [duo]
; Duo API host
host = api-eval.duosecurity.com
; Duo integration key
ikey =
; Duo secret key
skey =
|