Proxy only to an internal directory (e.g., show that it is not a subdirectory)

[nfld_republic]

Hi Folks,

I'm in the process of removing my nginx reverse proxy and using haproxy on my pfSense box. I have an internal site (actually, an IoT device) that I want externally to be directed to a specific subdirectory. In nginx, it was easy to do:

location / {
		include proxy_params;
		proxy_pass http://internal_server/subdirectory/;
		allow all;
	}

When connecting to the site, all that shows up in the web browser is https://site.external.com/ rather than https://site.externalcom/subdirectory

Based on my experimentation, this isn't a redirect. I banged my head off this for a week with Google University. I've found a fair number of people asking the same thing but there have been no responses.

Is this unobtainium or am I missing someting fundemental?

Thanks!