Hi Peter,
At least there's some progress. I think the advice to check the
Postfix config should be your next step - as mentioned earlier by
Robert Nichols, Look for "inet_interfaces =" in /etc/postfix/main.cf.
FirewallD and iptables are mutually exclusive in Fedora, with the
default being FirewallD. You have to make some deliberate decisions
to switch from FirewallD to the older iptables, so you should be good
- and are probably better off with FirewallD. There are some things
it can't quite do as well as iptables yet, but unless you hit one of
those (unlikely on a personal server) it's definitely the better and
easier option.
Andy