Chromecast on two different subnets

Good morning,

We have a chromecast with an IP on our LAN Client.
This must be used by users of our company, as well as external service providers who are connected to our Wifi Guest VLAN.
We opened the UDP ports: 1-65535 UDP and 8008-8009 in TCP from our Chromecast to these two subnets and vice versa.
We have also authorized port 1900 on our subnet at
We have also activated multicast on our 2 networks and activated the RP Candidate.
Despite this, we still cannot find the Chromecast when connected to our Guest Wifi.
I also specify that when I am on the internal wifi (client LAN), I can find the Chromecast on Google Chrome.
When I disconnect to connect to the Guest Wifi, I am able to stream normally to the chromecast.
The problem therefore seems to come from the discovery of this equipment in Guest Wifi.
Device discovery between networks does not seem to work.

Has anyone found a solution to make this work?



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    james.carsonjames.carson Moderator, WatchGuard Representative

    Hi @Mrouge

    This won't work on the Firebox as-is. One of two things would need to happen:

    -The Chromecast would need to be physically on the same network as the clients (the guest WiFi in this case.)
    [Also note, if client isolation is on for the Guest WiFi, it would need to be disabled to allow the devices and the Chromecast to talk with each other.]


    -You'll need to implement an mDNS reflector to send the Chromcast's discovery and other control traffic across VLANs. (Just setting up multicast won't work here, you need something to actually forward the traffic.)
    A few customers have reported success using AVAHI - https://avahi.org/

    There is an existing feature request, FBX-10140, to integrate this functionality into the firebox. If you'd like to follow that request, please open a support case and mention FBX-10140 in it somewhere - the tech that is assigned the case can set notifications for that request up for you.

    Thank you,

    -James Carson
    WatchGuard Customer Support

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    Good morning,

    This seems to match the information I was able to find on the internet.
    Thank you for this information.


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