anchor.diff:  # START PPTP
   #
   
  +EXPOSE 1723/tcp # PPTP Port must be standard(should not change?)
  +
   # https://groups.google.com/forum/#!topic/docker-user/dC6aIr4R1hY
   #
   # inspired by https://github.com/vimagick/dockerfiles/tree/master/pptpd
  
positive.code: # START OPENVPN
  # TBD
  
  # do not use the standard port
  ENV PORT_OPENVPN 11194
  EXPOSE $PORT_OPENVPN/tcp $PORT_OPENVPN/udp
  
  
  # inspired by https://github.com/gaomd/docker-openvpn-static
  
  
negative.code: # START SHADOWSOCKS
  #
  
  ENV PORT_SHADOWSOCKS 18388 # do not use the standard port
  EXPOSE ${PORT_SHADOWSOCKS}/tcp ${PORT_SHADOWSOCKS}/udp
  
  ENV SHADOWSOCKS_ENCRYPT_METHOD aes-256-cfb
  
  