OpenWRT 23.05: cannot add Chromecast

Installing and Using OpenWrt
1

I have recently upgraded my router to OpenWRT 23.05 and did a firmware reset on my Chromecast Ultra in order to reconnect it to the router.

The setup process is as follows:

  1. Chromecast and Phone are on the same WiFi network
  2. Phone recognizes Chromecast during setup process via Bluetooth
  3. Chromecast recognizes WiFi network of phone and connects to the same WiFi. No issues
  4. Phone tries to connect to Chromecast via WiFi and fails: Cannot find Chromecast. Google Home tells something about client isolation - however my WiFi clients are not isolated from each other
  5. Chromecast is properly connected to the Internet: shows background image reel, correct time etc.
  6. I can ping Chromecast from the Phone without issues. However Google Home on the same Phone cannot find it.

It previously worked with OpenWRT 19.07. Is there something I can try (except reverting to old OpenWRT)?

2

Silly thing but it might help: set WiFi network to channel 36 and try then. Chromecast with Google TV requires this, for example.

3

Please connect to your OpenWrt device using ssh and copy the output of the following commands and post it here using the "Preformatted text </> " button:
grafik
Remember to redact passwords, MAC addresses and any public IP addresses you may have:

ubus call system board
cat /etc/config/network
cat /etc/config/wireless
cat /etc/config/dhcp
cat /etc/config/firewall
4

Thanks for trying to help! After searching the web it looks like more Chromecast users have this issue and not everyone is using OpenWRT. Obviously Chromecast / Google Home is getting upset with ever so slight network changes. Nicely done Google! Let's see if this settles down after a while. I will keep you updated.

2 Likes
5

Hi,

just an update and the solution: since I am a DSL user I thought it was a good idea to limit the MTU to 1492 for LAN bridge and WiFi. This did not have an effect on the DSL connection and everything internet-related continued to work smoothly. Also ping worked without issues (as it uses small packets).

But within my LAN, devices could not communicate with each other properly. They probably expect a MTU of 1500 to work inter-LAN (, but they do not expect a MTU of 1500 to work via the internet?)

I am still puzzled that the LAN devices did not discover a MTU of 1492. Shouldn't this work automatically? Do I need to set additional flags when setting a MTU of 1492? It looks like MTU was handled differently in older versions of OpenWRT?

6

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