Importing Existing Cluster

We want to use rancher to manage several k3s clusters. Are there any firewall rules I need to open to allow traffic between rancher and the existing cluster? I ran the kubectl apply command in the first downstream cluster, and it seemed to work, but I don’t understand how they’re communicating.

Thanks

Please check the documentation on what ports need to be open. If your firewall is disabled, then it will just work. https://ranchermanager.docs.rancher.com/getting-started/installation-and-upgrade/installation-requirements/port-requirements