We have a hosted website, configurable through cPanel. Content that can't be hosted there (because it requires up-to-date PHP, which is "coming soon") is temporarily on another server. That server has a permanent IP address, but no URL.
What are the cPanel options we need to use to get subdomain.example.com to display content from 203.0.113.0, whilst maintaining the original URL? So e.g. if a user types subdomain.example.com/page, they get content from 203.0.113.0/page, but continue to see subdomain.example.com/page in their browser.
Edit for more info:
The original server is viewed at a URL (say example.com). It is hosted with Zen Internet, and my only editing power is through limited cPanel features. I think it's running Apache. I can add new files. I'm struggling to match cPanel documentation with my experience of e.g. hosting an Apache server from a laptop. (Which is something I've only done a couple of times.)
I can ask our admin to edit DNS records / talk to our hosting provider, but his experience is as limited as mine, so I need to pass along specific instructions. I believe our admin has created a DNS A record which points at the IP address. Unless I add a redirect in cPanel, however, I get sent to a Zen Internet Domain Holding Page. (First I get a "the security certificate is from Zen hosting..." warning, but ignoring that...)
The subdomain server is accessed through a public IP address (say 203.0.113.0:8080). It is an IIS server. It is configured to display the subdomain content if it receives a request from subdomain.example.com, or at port :8080; viewing the site via the IP+port works fine. This server I have full access to.