[SSSD-users] Config for joining AD forest and Kerberos cross-domain authentication

Hi, we are looking for a detailed configuration example to join an AD forest with working Kerberos authentication. Our AD infrastructure consists of a single forest with multiple (sub-)domains in two-way trust. No FreeIPA, just Windows 2012 AD servers and SSSD clients using version 1.11 and 1.15 on Debian. We can successfully join with sssd-ad using the "net ads join" command and users from the same domain can authenticate using a Kerberos ticket or password. Also mounting CIFS shares via pam-mount works fine in the same domain. Unfortunately, users from other domains can't use their Kerberos ticket, only password works. These users are specifying their domain on login. Surprisingly, once logged in after authenticating with a password, foreign-domain users are able to issue a Kerberos ticket with kinit if they specify username@FQDN (with capital letters). Also lookup up group membership of users from another domain works fine, so presumably the LDAP part is working correctly. This is our current config, are we missing something in order to get Kerberos cross-domain authentication working? $ cat /etc/sssd/sssd.conf [sssd] domains = sub1.example.com services = nss, pam, pac config_file_version = 2 [nss] filter_groups = root filter_users = root [pam] [domain/sub1.example.com] id_provider = ad auth_provider = ad chpass_provider = ad access_provider = ad cache_credentials = true ldap_referrals = false ldap_force_upper_case_realm = true ad_gpo_access_control = disabled override_homedir = /home/%u default_shell = /bin/bash Thanks and kind regards, Bastian