So I was setting up KDE connect and I noticed that the default firewall setup on Fedora 23 blocks KDE connect. Fortunately, fixing it is simple. Just create a new service definition called kde-connect.xml like below and put it in /etc/firewalld/services

<?xml version="1.0" encoding="utf-8"?>
  <short>KDE Connect</short>
  <description>KDE Connect is a project that aims to communicate all your devices.</description>
  <port protocol="tcp" port="1714-1764"/>
  <port protocol="udp" port="1714-1764"/>

I had to restart firewalld to get it to recognize the new service file: systemctl restart firewalld.service. After that, just add the service like so: firewall-cmd --permanent --add-service kde-connect