Title: #971: AD: use getaddrinfo with AI_CANONNAME to find the FQDN
But in theory this is a change in behavior and I wonder if there are
setups which are carefully crafted so that with a short hostname everything works as
I honestly do not know and maybe they exist, but what I found is that when the
short hostname is used dynamic DNS updates break.
Although the used ad_hostname is already printed in the logs with
level SSSDBG_CONF_SETTINGS, I think it is worth to add another message in case the short
name is expanded which explains that ad_hostname should be set explicitly if SSSD should
really use a short name.
Done, good idea.
See the full comment at https://github.com/SSSD/sssd/pull/971#issuecomment-576659648