anchor.diff:  CMD [ "start" ]
   
   WORKDIR $ACROSSFW_HOME
  -COPY . .
   RUN ln -s /etc/service /service \
     && ln -s ${ACROSSFW_HOME}/service/vpnet /service/vpnet
   
  
positive.code:     	iptables \
      	net-tools \
      	netcat \
      	tcpdump \
      	tinc
  
  
negative.code: #
  #
  
  # put COPY . . the end of Dockerfile for speedup build time by maximum cache usage
  COPY . .
  
  # Clean up APT when done.
  RUN apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
  