Same server- httpd port 80 index.html links to squid
 

I have one server running apache with a single index.html page with links like this:
<a href=http://SOME-etc-host1-host/>displayed-link1</a>
<a href=http://SOME-etc-host2-host/>displayed-link2</a>
<a href=http://SOME-etc-host3-host/>displayed-link3</a>
<a href=http://SOME-etc-host4-host/>displayed-link4</a>

Apache is running on port 80 while squid is running as a reverse proxy on port 81.

What I need is href link (and future script) to go to the same squid server port 81. for reverse proxy caching.

These are on the SAME server... what's the possible point in caching??? You would really want to swap the ports over. if squid is front end to serving the site, it needs to be on port 80.

I don't have control of DNS. A page with links from apache :80 to squid :81 solves this. Ultimately I will invoke an LDAP auth to invoke a script to log users into remote systems.

I hope...

This has nothing to do with DNS, and even less to do with LDAP. I'm lost what you're trying to actually achieve now.

A collection of devices reside on internal and external network with little capacity to audit, authenticate or build rules limiting use of the devices.
My desire would be to use one box with Apache/Squid leveraging login/auth NTLM either with apache or squid. On the north side, launch a script to push to devices to authenticate each device.

To more clearly define the need. I need a mitm to examine and control. MITMPROXY may help with this.

OK, so this *might* be exactly what I have at home. I've an apache instance on 80 and 443 with authentication enabled for all uris with a standard htpasswd file. Most urls are proxied to different ports, 8080, 8081, 8082 where different apps are running, so I get the ssl, authentication and auditing completely in apache. If so, that's just basic mod_proxy stuff for the proxying.

I'm not sure.
The remote devices are all over the place and I can't modify ports on the devices. Basically:

user -------------proxy---------------------intra and internet https://devices (multiple devices running port 443)

well it doesn't have to be on the same box. that was just my own case.

In the method you expressed are you able to then content filter/audit that which originates from the SSL urls?

there are plenty of ways to check protocols in apache, If you only want SSL urls though, just don't configure it for anything else.