This post describes how you can unblock port 9001 to allow Etherpad traffic through in the Fedora firewall.
Unblocking port 9001 so traffic can get through to Etherpad
By default Fedora 27 has a firewall which blocks traffic reaching port 9001. This stops you being able to access Etherpad on this port.
One of the ways to get around this is to forward port 9001 to another port that is accessible. However I wanted to use port 9001 for Etherpad so I had to change the firewall to make it accessible externally.
To disable this permanently and reload the firewall configuration so it’s immediately available you can run the following command.
firewall-cmd --permanent --add-port=9001/tcp
systemctl restart firewalld
This adds an exception for the Ehterpad service and unblocks port 9001 on a permanent basis.
This should ensure that even after reboots it should stay unblocked.