Enabling IGMP and broadcast in firewalld for Linux Roon server

Please note that this should be UDP 9003.

I’m afraid I can’t help you too much from a Fedora point of view, but the settings for Ubuntu 18.04 below whilst based on UFW do translate fairly readily into iptables which should be easier to decipher. You’ll need to adjust for your subnet.

sudo ufw allow from 192.168.1.0/24 to any port 9100:9200 proto tcp
sudo ufw allow from 192.168.1.0/24 to any port 9003 proto udp
sudo ufw allow from 192.168.1.0/24 to any port 1900 proto udp

sudo nano /etc/ufw/user.rules

### IGMP ###
-A ufw-user-input -s 224.0.0.0/4 -j ACCEPT
-A ufw-user-input -d 224.0.0.0/4 -j ACCEPT
-A ufw-user-input -s 240.0.0.0/5 -j ACCEPT
-A ufw-user-input -m pkttype --pkt-type multicast -j ACCEPT
-A ufw-user-input -m pkttype --pkt-type broadcast -j ACCEPT

The first 3 lines above could be achieved using sudo ufw allow from ... but the later are too complex. However, line 4 is equivalent to firewall-cmd --permanent --direct --add-rule ipv4 filter INPUT 0 -m pkttype --pkt-type multicast -j ACCEPT.