On PureOS a Debian based Linux
A kind person(online) helped me install Caddy with this docker command:
sudo docker run --name caddy -d -p 8080:80 -p 8443:443 -v /home/sherab/Caddy/config:/config -v /home/sherab/Caddy/data:/data -v /home/sherab/Caddy/config/Caddyfile:/etc/caddy/Caddyfile --restart unless-stopped caddy
here’s how it looks like
07a22eac980b caddy "caddy run --config …" 2 days ago Up 2 days 2019/tcp, 0.0.0.0:8080->80/tcp, 0.0.0.0:8443->443/tcp caddy
Caddy is now installed on a machine (192.168.1.153) that has a running nextcloudpi instance(with docker).
c8585711b820 ownyourbits/nextcloudpi "/run-parts.sh shera…" 13 months ago Up 3 months 0.0.0.0:80->80/tcp, 0.0.0.0:443->443/tcp, 0.0.0.0:4443->4443/tcp nextcloudpi
I have two folders ~/caddy and ~/Caddy
in ~/Caddy/config/Caddyfile I have these two entries:
sherab.ddns.net {
reverse_proxy http://192.168.1.153
}
sherab.workisboring.com {
reverse_proxy http://192.168.1.94
}
When visiting localhost on my browser I get a Caddy works! slanted page.
Now - what should I do next (remeber - noob 
)
How do I connect from the outside world to my machines?
Each machine has its own nextcloudpi instance needing a Letsencrypt cert(I undrestand that this is where Caddy as reverse proxy can help)
Domain 1 → 192.168.1.94 (nextcloudpi on this machine is working locally but has no letsencrypt)
Domain 2 → 192.168.1.153 (nextcloudpi on this machine is already working and has letsencrpyt)(prot forwarding is working external 80 & 443 to internal 80 and 443)
I suppose my main problem is not knowing how to prot forward to caddy because caddy is in a docker container - which will have a different IP??
What should I do next
Kind regards
Sherab