/usr/share/samba/setup/krb5.conf is in samba4 4.0.0~alpha18.dfsg1-4ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 | [libdefaults]
default_realm = ${REALM}
dns_lookup_realm = false
dns_lookup_kdc = true
|