instruction: Create a comprehensive Dockerfile for networking applications with best practices
output: ```dockerfile
  from the container will masquerade, using the
  host's IP address.In docker inspect, this port mapping will be shown as follows. Note that
  there is no HostPort for IPv6, because it is using routed mode:
  
  $ docker container inspect <id> --format "{{json .NetworkSettings.Ports}}"
  {"80/tcp":[{"HostIp":"0.0.0.0","HostPort":"8080"},{"HostIp":"::","HostPort":""}]}
  Alternatively, to make the mapping IPv6-only, disabling IPv4 access to the
  container's port 80, use the unspecified IPv6 address [::] and do not
  include a host port number:
  
  $ docker run --network mynet -p '[::]::80'
  Setting the default bind address for containersBy default, when a container's ports are mapped without any specific host
  address, the Docker daemon binds published container ports to all host
  addresses (0.0.0.0 and [::]).For example, the following command publishes port 8080 to all network
  interfaces on the host, on both IPv4 and IPv6 addresses, potentially
  making them available to the outside world.
  
  docker run -p 8080:80 nginx
  You can change the default binding address for published container ports so that
  they're only accessible to the Docker host by default. To do that, you can
  configure the daemon to use the loopback address (127.0.0.1) instead.
  WarningIn releases older than 28.0.0, hosts within the same L2 segment (for example,
  hosts connected to the same network switch) can reach ports published to
  localhost. For more information, see
  moby/moby#45610To configure this setting for user-defined bridge networks, use
  the com.docker.network.bridge.host_binding_ipv4
  driver option when you create the network.
  
  $ docker network create mybridge \
   -o "com.docker.network.bridge.host_binding_ipv4=127.0.0.1"
  
  NoteSetting the default binding address to :: means port bindings with no host
  address specified will work for any IPv6 address on the host. But, 0.0.0.0
  means any IPv4 or IPv6 address.Changing the default bind address doesn't have any effect on Swarm services.
  Swarm services are always exposed on the 0.0.0.0 network interface.Default bridgeTo set the default binding for the default bridge network, configure the "ip"
  key in the daemon.json configuration file:
  
  {
   "ip": "127.0.0.1"
  }This changes the default binding address to 127.0.0.1 for published container
  ports on the default bridge network.
  Restart the daemon for this change to take effect.
  Alternatively, you can use the dockerd --ip flag when starting the daemon.Docker on a routerOn Linux, Docker needs "IP Forwarding" enabled on the host. So, it enables
  the sysctl settings net.ipv4.ip_forward and net.ipv6.conf.all.forwarding
  it they are not already enabled when it starts. When it does that, it also
  sets the policy of the iptables FORWARD chain to DROP.If Docker sets the policy for the FORWARD chain to DROP. This will prevent
  your Docker host
  ```