Make openSUSE work with Chromecast, getting to know your firewall zone in Linux.

You might find yourself having a hard time making Chromecast work on your openSUSE or Linux-box in general. Well, the issue lies in your firewall settings.

In this article, I will focus on firewalld, a zone-type firewall - rules based on zone, that's pre-installed in openSUSE, Fedora, etc. You can skip this article if you're using ufw that's pre-installed in Ubuntu.

Basically, all you need to do is:

nmcli connection modify 'YourConnectionName' connection.zone home

This setting will change your connection to the home zone that will be more compromised than the default public zone, allowing you to connect with your Chromecast devices. This setting will also persist on reboot, so you only have to do it once. I will explain in detail below.

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Do not change your device zone, change a connection zone instead

Why changing your device/interface zone is a bad idea? Let's assume that on this interface, a wireless card in your laptop, for example, you might use to connect to your home's wifi hotspot, your school's wifi hotspot, coffee shop's wifi hotspot, etc. Well, you wouldn't trust all those hotspots equally, would you? Yes, that's why changing your device/interface zone is a bad idea. And that's also the reason why the device/interface zone is set to public by default. It's needless to say that changing the default zone, or open a specific port range, would be the worst idea 😂

I recommend you change your most trusted connection zone, your home network, for example, to home, so you can use Chromecast on this network, along with many connection types that wouldn't work otherwise.

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Knowing your current connection zone, and changing the zone

It's surprisingly hard to find your connection zone, as the zone is not presented in GNOME Settings (issue #1425), nor YaST Firewall. Google doesn't help much either. Here's how to find your zone before making any change.

1. Finding your active connection name first:
   

   nmcli connection show --active
   

    

   This will return something like:
   

   NAME                UUID                           TYPE  DEVICE 
   YourConnectionName  xxxxxxxxxxxxxxxxxxxxxxxxxxxxx  wifi  xxxxxx
   

    

2. Finding its zone:
   

   nmcli connection show 'YourConnectionName' | grep zone
   

    

   This will return:
   

   connection.zone:                        public
   

    

3. Changing your connection zone to home
   

   nmcli connection modify 'YourConnectionName' connection.zone home
   

    

4. Checking your connection zone again:
   

   nmcli connection show 'YourConnectionName' | grep zone
   

    

   It should return:
   

   connection.zone:                        home
   

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After this, you should be able to cast to Chromecast devices on openSUSE or any system with firewalld. It's worth to check whether you have the default allowed services on your home zone in YaST Firewall. You should have dhcpv6-client, mdns, samba-client, and ssh services on the allowed list.

I hope this helps.

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Cover photo by Viktor Forgacs on Unsplash

Zone on The Road photo by David Clarke on Unsplash

A Map photo by Hendrik Morkel on Unsplash