Is there a way to cast to Google Home from Chrome browser, if the smart speaker is on the different network? I know Google says devices should be on the same network, but maybe there are some hacks?
Okay, figured it out.
To make devices to appear on the same subnet, you may create a network bridge. This way devices, even connected to separate physical interfaces of the server, may be actually in one subnet.
But there is not only a requirement for devices to be in the same subnet.
I've investigated that the Google Home not just merely accepts packets from a casting device. It also wants to be able to ping the caster (ICMP) and send packets to the multicast address 184.108.40.206, over UDP protocol, to port 5353.
Google casting support page says that traffic to Google Home should be unrestricted, but says nothing about the fact that the smart speaker should be able to send some packets over the network, too.
I've unfirewalled this traffic and now casting to Google Home works.
When you say a different network, are you saying on a different physical network, different subnet, or separated by VLAN?
If you are different physical networks, I don't think it's going to work without creating using VPN. If you're on separate subnets or VLANs you could create static routes between them.