a bit of a hack to allow traefik to redirect to external hosts using nginx as a relay container
There are now better ways to do that but I think they only work with static changes to traefik.toml
Edit the proxy-pass IP in nginx/default.conf
Edit proxy.yaml and change settings to expose your nginx container on the URL you want you external IP to respond.
docker build . -t nginx-external
docker stack deploy proxy -c proxy.yaml