instruction: Create a comprehensive Dockerfile for networking applications with best practices
output: ```dockerfile
  from the host and other containers.overlayOverlay networks connect multiple Docker daemons together.ipvlanIPvlan networks provide full control over both IPv4 and IPv6 addressing.macvlanAssign a MAC address to a container.For more information about the different drivers, see Network drivers
  overview.Connecting to multiple networksA container can be connected to multiple networks.For example, a frontend container may be connected to a bridge network
  with external access, and a
  --internal network
  to communicate with containers running backend services that do not need
  external network access.A container may also be connected to different types of network. For example,
  an ipvlan network to provide internet access, and a bridge network for
  access to local services.When sending packets, if the destination is an address in a directly connected
  network, packets are sent to that network. Otherwise, packets are sent to
  a default gateway for routing to their destination. In the example above,
  the ipvlan network's gateway must be the default gateway.The default gateway is selected by Docker, and may change whenever a
  container's network connections change.
  To make Docker choose a specific default gateway when creating the container
  or connecting a new network, set a gateway priority. See option gw-priority
  for the
  docker run and
  docker network connect commands.The default gw-priority is 0 and the gateway in the network with the
  highest priority is the default gateway. So, when a network should always
  be the default gateway, it is enough to set its gw-priority to 1.
  
  $ docker run --network name=gwnet,gw-priority=1 --network anet1 --name myctr myimage
  $ docker network connect anet2 myctr
  Container networksIn addition to user-defined networks, you can attach a container to another
  container's networking stack directly, using the --network container:<name|id> flag format.The following flags aren't supported for containers using the container:
  networking mode:--add-host--hostname--dns--dns-search--dns-option--mac-address--publish--publish-all--exposeThe following example runs a Redis container, with Redis binding to
  localhost, then running the redis-cli command and connecting to the Redis
  server over the localhost interface.
  
  $ docker run -d --name redis example/redis --bind 127.0.0.1
  $ docker run --rm -it --network container:redis example/redis-cli -h 127.0.0.1
  Published portsBy default, when you create or run a container using docker create or docker run,
  containers on bridge networks don't expose any ports to the outside world.
  Use the --publish or -p flag to make a port available to services
  outside the bridge network.
  This creates a firewall rule in the host,
  mapping a container port to a port on the Docker host to the outside world.
  Here are some examples:Flag valueDescription-p 8080:80Map port 8080 on the Docker host to TCP port 80 in the container.-p 192.168.1.100:8080:80Map port 8080 on the Docker host IP 192.168.1.100 to TCP port 80 in the container.-p 8080:80/udpMap port 8080 on the Docker host to UDP port 80 in the container.-p 8080:80/tcp -p 8080:80/udpMap TCP port 8080 on the Docker host to TCP port 80 in the container, and map UDP port 8080 on the Docker host to UDP port 80 in the container.
  ImportantPublishing container ports is insecure by default. Meaning, when you publish
  a container's ports it becomes available not only to the Docker host, but to
  the outside world as well.If you include the localhost IP address (127.0.0.1, or ::1) with the
  publish flag, only the Docker host and its containers can access the
  published container port.
  
  $ docker run -p 127.0.0.1:8080:80 -p '[::1]:8080:80' nginx
  
  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#45610If you want to make a container accessible to other containers,
  it isn't necessary to publish the container's ports.
  You can enable inter-container communication by connecting the containers to the
  same network, usually a bridge network.Ports on the host's IPv6 addresses will map to the container's IPv4 address
  if no host IP is given in a port mapping, the bridge network is IPv4-only,
  and --userland-proxy=true (default).For more information about port mapping, including how to disable it and use
  direct routing to containers, see
  packet filtering and firewalls.IP address and hostnameWhen creating a network, IPv4 address allocation is enabled by default, it
  can be disabled using --ipv4=false. IPv6 address allocation can be enabled
  using --ipv6.
  
  $ docker network create --ipv6 --ipv4=false v6net
  By default, the container gets an IP address for every Docker network it attaches to.
  A container receives an IP address out of the IP subnet of the network.
  The Docker daemon performs dynamic subnetting and IP address allocation for containers.
  Each network also has a default subnet mask and gateway.You can connect a running container to multiple networks,
  either by passing the --network flag multiple times when creating the container,
  or using the docker network connect command for already running containers.
  In both cases, you can use the --ip or --ip6 flags to specify the container's IP address on that particular network.In the same way, a container's hostname defaults to be the container's ID in Docker.
  You can override the hostname using --hostname.
  When connecting to an existing network using docker network connect,
  you can use the --alias flag to specify an additional network alias for the container on that network.DNS servicesContainers use the same DNS servers as the host by default, but you can
  override this with --dns.By default, containers inherit the DNS settings as defined in the
  /etc/resolv.conf configuration file.
  Containers that attach to the default bridge network receive a copy of this file.
  Containers that attach to a
  custom network
  use Docker's embedded DNS server.
  The embedded DNS server forwards external DNS lookups to the DNS servers configured on the host.You can configure DNS resolution on a per-container basis, using flags for the
  docker run or docker create command used to start the container.
  The following table describes the available docker run flags related to DNS
  configuration.FlagDescription--dnsThe IP address of a DNS server. To specify multiple DNS servers, use multiple --dns flags. DNS requests will be forwarded
  ```