Chromecast issues when on same VLAN as HA

Configuration
1

Brief:

  • I have a separate vlan for my IoT devices on my Ubiqutiy Unify Dream Machine router.
  • When my HASS is on that same IoT network, then Chromecasts (especially CCAs) do not work properly: groups fail to play, devices disappear. :frowning_face:
  • When the HASS machine (a Pi4) is on a separate VLAN (and consequently a separate IP block), things work as they should. :smiley:

Some more detail:

  • The VLAN for my IoT devices has the ip block 192.168.4.*
  • The VLAN for my primary computers is 192.168.2.*
  • Without thinking about it, my Raspberry Pi that runs HASS was on the primary network, while all the IoT devices (including Google devices) were on the IoT network.
  • This worked fine.
  • But, I couldn’t send WOL packets from HA to my LG TV (to power on the TV)
  • So, I moved the HA to the IoT network (and that worked, the TV turns on)
  • After doing so, all my Chromecast groups, and Chromecast Audio (CCA) devices all started acting up.
  • I didn’t realize this was the cause, so I tried a bunch of things.
    • All of my CCAs are hardwired via ethernet. Putting them on WiFi did not help.
    • I even deleted my old Home and factory reset all the CCAs, thinking that they just all got confused.
    • I messed with my router settings extensively based on many online topics

My setup

  • Ubiquity Unifi Dream Machine (UDM)
  • Some managed switches, a few wireless access points
  • 4 CCAs (hard wired using POE adapters)
  • 1 CCwGTV (hard wired using the official ethernet plug adapter)
  • 1 Google Home
  • 1 Google Home Mini
  • 1 Nest Audio

Question

  • Why? What about having the HASS Pi on the same VLAN / subnet could cause this?
  • How? How should I solve this, I suppose I can put just the Google devices on their own VLAN.

Related (mostly for keywords)
There are so many posts on the internet about CCAs, ethernet, mDNS, speaker groups, etc etc that sound almost exactly like what I was dealing with. Would somebody help me understand how the mDNS communication protocol of Chromecast devices could be disrupted by a device (in my case the HASS).

2

Hello did you get anywhere with this problem think I’ve been suffering similar for a while. Manly spamming the log files and Google devices not communicating with HA when a voice command is given. Sometimes the Google devices have a massive lag even when the question,/command is not HA related
also using a UDM,
problem finally moved up the list so I’m trying to fix it once and for all.
Thank you

3

My “Solution” was to move my HA to my “corporate” VLAN, leaving all other devices (including CC*) on the IoT VLAN. I don’t really want HA to be on corporate, but everything is working this way. The next step for me is to either put HA on its own VLAN (and setup isolation rules to project the corporate vlan), or move all google devices to their own vlan so they only see each other.

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