docker: ipsec vpn server + mitmproxy

docker-compose.yml

version: "3"

services:
  vpn:
    image: hwdsl2/ipsec-vpn-server
    env_file:
      - ./vpn.env
    ports:
      - "500:500/udp"
      - "4500:4500/udp"
    privileged: true
    hostname: ipsec-vpn-server
    container_name: ipsec-vpn-server
    volumes:
      - /lib/modules:/lib/modules:ro
    command: >
      bash -c '
      HOST=$$(host -4 mitmproxy | head -1 | awk "{ print \$$4 }") &&
      echo "HOST: $$HOST" &&
      iptables -t nat -A PREROUTING -i eth+ -p tcp --destination-port 80 -j DNAT --to-destination $$HOST:8080 &&
      iptables -t nat -A PREROUTING -i eth+ -p tcp --destination-port 443 -j DNAT --to-destination $$HOST:8080 &&
      /opt/src/run.sh
      '

  mitmproxy:
    image: mitmproxy/mitmproxy
    ports:
      - "8080:8080/tcp"
    hostname: mitmproxy
    container_name: mitmproxy
    command: mitmdump -T --host

vpn.env

# Define your own values for these variables
# - DO NOT put "" or '' around values, or add space around =
# - DO NOT use these special characters within values: \ " '
VPN_IPSEC_PSK=foobar
VPN_USER=foo
VPN_PASSWORD=bar

how to connect vpn?

user,passwd...

Using this creates a recursive request loop, where it keeps trying to loop through mitmproxy to make the request.
Any idea on how to stop this from happening? I'm at wits end.