It's correct that the network argument of the docker run command only supports one network. But we can connect another network card to our container.
create multiple networks
- docker network create --driver bridge net1
- docker network create --driver host net2
run the container using the initial network and connect it to the other network.
- docker run -it --name Ubuntu --network net1 Ubuntu
- docker network connect net2 Ubuntu
Hope this will help you.