I'm running linux - Fedora 23 on a laptop. chromecast works. For instance, I can cast netflix from chrome.
The internal network is 10.10.10.0, which includes the laptop and the chromecast. No firewall on the laptop.
I get a popup about firewall problems, which gives som iptables commands. Many new distributions have switched to firewallD. For those you need:
firewall-cmd --add-port=5556/tcp
firewall-cmd --add-port=5558/tcp
sean