To follow on Gilbert's RHEL7 firewalld, chrony, etc, questions. I also, on every new Fedora box (except basic single-user laptops, etc), ditch NetworkManager, and change MTA back to sendmail. That last one is tricky as the supported way is a bit weird (but easy when you know the trick):
alternatives --config mta
Make sure you have sendmail rpm's installed first. After you switch to sendmail you can rpm -e the postfix stuff.
Yes, my boxes are all pretty much Redhat 9.0 (*pre-RHEL*!!!) plus systemd. Just the way I like it! The things that are supposed to make our lives "simpler" or "better" just get in the way, slow me down, introduce new bugs, make me learn a whole new set of quirks, and force me to forget the old. All pain, and no gain. Change for change's sake. Windows anyone?