Unifi Controller SSL reverse proxy for port 443

haproxy.cfg

global
	log /dev/log	local0
	log /dev/log	local1 notice
	chroot /var/lib/haproxy
	stats socket /run/haproxy/admin.sock mode 660 level admin expose-fd listeners
	stats timeout 30s
	user haproxy
	group haproxy
	daemon

	# Default SSL material locations
	ca-base /etc/ssl/certs
	crt-base /etc/ssl/private

	# Default ciphers to use on SSL-enabled listening sockets.
	# For more information, see ciphers(1SSL). This list is from:
	#  https://hynek.me/articles/hardening-your-web-servers-ssl-ciphers/
	# An alternative list with additional directives can be obtained from
	#  https://mozilla.github.io/server-side-tls/ssl-config-generator/?server=haproxy
	ssl-default-bind-ciphers ECDH+AESGCM:DH+AESGCM:ECDH+AES256:DH+AES256:ECDH+AES128:DH+AES:RSA+AESGCM:RSA+AES:!aNULL:!MD5:!DSS
	ssl-default-bind-options no-sslv3

defaults
	log	global
	mode	http
	option	httplog
	option	dontlognull
        option  forwardfor
        option  http-server-close
        timeout connect 5000
        timeout client  50000
        timeout server  50000
	errorfile 400 /etc/haproxy/errors/400.http
	errorfile 403 /etc/haproxy/errors/403.http
	errorfile 408 /etc/haproxy/errors/408.http
	errorfile 500 /etc/haproxy/errors/500.http
	errorfile 502 /etc/haproxy/errors/502.http
	errorfile 503 /etc/haproxy/errors/503.http
	errorfile 504 /etc/haproxy/errors/504.http

frontend www-publc
        bind :::80 v4v6
        bind :::443 v4v6 ssl crt /root/unifi.int.bjs.crt
        http-request set-header X-Forwarded-Port %[dst_port]
        http-request add-header X-Forwarded-Proto https if { ssl_fc }

        use_backend unifi if { hdr(Host) -i unifi.int.bjs }

backend unifi
        server unifi 127.0.0.1:8443 ssl verify none

Thank you for sharing that snippet!
Do you know how to pass the STUN and Inform Port through the HAProxy, so that the host running the unifi controller is not exposed? Or is it only possible with port redirection?

@SchulteMK Unfortunately STUN is a UDP protocol and HAProxy is not able to proxy it, so unfortunately you're not going to be able to do that with HAProxy.

Furthermore, STUN requires unmodified IP headers. You essentially need direct packet-level connection between server and client. You cannot proxy it.