I think you want header_upstream instead of proxy_header, at least in newer versions of Caddy, and the transparent[0] preset sets Host, X-Forwarded-For, and X-F

I think you want header_upstream instead of proxy_header, at least in newer versions of Caddy, and the transparent[0] preset sets Host, X-Forwarded-For, and X-Forwarded-Proto for you! proxy / 127.0.0.1:8080 { except /favicon.ico /robots.txt /assets /plainpages /staticstuff /test1 transparent } 0. https://caddyserver.com/docs/proxy https://caddyserver.com/docs/proxy