I am new with docker and have installed docker in rootless mode, which works just fine. The problem is that with this the guides for firewall with docker does not work (I have no network-interface 'docker0' nor a iptables-chain 'DOCKER-USER') and I could not find a site which explains how to setup a firewall for docker-rootless.
My specific use-case is to control outgoing traffic from the containers (so that they can only use 443 and the ports of common E-Mail Protocols).
Does anyone know how to accomplish this or can give me links to websites which explain this?