Yes, FreeIPA is Kerberos+LDAP+X.509 CA, and GSSAPI is in OpenSSH (normally with the key exchange patch). SSSD is a local mechanism, not network authentication.

Yes, FreeIPA is Kerberos+LDAP+X.509 CA, and GSSAPI is in OpenSSH (normally with the key exchange patch). SSSD is a local mechanism, not network authentication. I mentioned authorized keys distribution mechanisms elsewhere, but I was thinking authentication (c.f. OIDC), not authorization.