for it to listen on all interfaces for that specific port. Notice that you need to remove the “network_mode: host” to be able to mapp ports. you will need to mapp all the ports that the service is using.

version: "3.5"
services:
    i2p:
        image: geti2p/i2p
        network_mode: host
        volumes:
            - ./i2pconfig:/i2p/.i2p
            - ./i2ptorrents:/i2psnark
    ports:
      - 7657:7657