Chromecast Debugging (and where is avahi-browse?)

[Aviewanew]

I run a gentoo box as a router/firewall, using Shorewall as the firewall for the external and internal interface's firewalls. I segment users of the network into /8's.

My machines can talk to my Chromecast. Another user's machines cannot. Despite the fact that the Chromcast sits inside their /8 (inside their machine's /24 in fact)!

I cannot find any sort of shorewall configuration (rules/policy/hosts options, etc) that would cause different behavior between the two users.

While attempting to debug the chromecast queries, I was using the following dig query from the router:

[Hu]

According to equery use avahi, the avahi-browse program is only built if you have USE=utils.

For your original problem, please describe in more detail the failure for the machines that cannot use Chromecast. What happens when they try to use it? What should have happened instead? What network traffic does tcpdump show for both the good and bad cases?