Great!īut it didn’t work completely - audio groups didn’t appear in the cast target list. With this configuration, it was possible to cast from a trusted device to a Chromecast on the untrusted network. MDNS (Multicast DNS) setting in UniFi Controller

Block LAN to WLAN Multicast and Broadcast Data - off ❎ ( Wireless Networks section under Advanced Options) - not mentioned in the UniFi best practices article.

Enable Multicast DNS service - on ✅ ( Services section under MDNS) - more on this later.

Confusingly, some posts online suggest this should be disabled for Chromecast to work. Enable multicast enhancement (IGMPv3) - on ✅ ( Wireless Networks section under Advanced Options)- This limits the multicast traffic that is sent to client devices that aren’t participating in a particular multicast group.A UniFi article on Managing Broadcast Traffic goes into this in more detail. Internet Group Management Protocol (IGMP) snooping is designed to prevent hosts on a local network from receiving traffic for a multicast group they have not explicitly joined. Enable IGMP snooping - on ✅ ( Networks section, works only if you have a UniFi Switch) - Networks need to manage broadcast and multicast traffic because otherwise it eventually degrades the network health.Ubiquiti have a support article on UniFi Best Practices for Managing Chromecast/Google Home which goes through how to configure a UniFi network so you can cast to Chromecast devices on a separate VLAN. It might work for you if you have a similar setup, though it won’t work on a UniFi Dream Machine (UDM) for reasons described below. My network is built around a UniFi Security Gateway (USG3), a UniFi US-8–60W Switch, UAP-AC-Pro Access Points, with the controller running on a first generation UniFi Cloud Key, all with latest stable release software as of February 2021. Hopefully it might save someone else some time. I figured this out after a lot of searching and finding inconsistent answers. I wanted to have the protection of putting Chromecast devices on this network, and still be able to cast to them from devices on the trusted and guest networks. I have a separate “Internet of Things” network to limit the potential impacts from untrusted devices around the house.

Google Chromecast on a separate VLAN with UniFi Security Gateway

Unifi discovery chrome pluggin