I'm going to reply to self here since I found out something interesting: If I join a
Fedora 23 host with the new adcli (resulting in the lower-case host/ SPNs) and use my
sssd.conf [0], lookups work!
I suspected the problem was fixed somewhere between SSSD versions in CentOS 7.2 (1.13.0)
and Fedora 23 (1.13.3), so I had a look over the release notes, but I couldn't find
anything related to my problem…
[0]
https://lists.fedorahosted.org/archives/list/sssd-users@lists.fedorahoste...