I am trying to setup an easy rule during my httpd.conf like a precursor to more complex rules I have to setup.

Basically make use of this:

RewriteCond %{REQUEST_URI} ^/test\.txt
RewriteRule ^(.*)$ http://127.0.0.1:8080 [R,L]

... a request /test.txt would go to port 8080, not surprisingly.

But when I give a ! to switch the REQUEST_URI match, such as this:

RewriteCond %{REQUEST_URI} !^/test\.txt
RewriteRule ^(.*)$ http://127.0.0.1:8080 [R,L]

... then every request will get delivered to port 8080, including demands for /test.txt. I had been expecting text.txt to become permitted through since the RewriteCond could be using the next rule to each request that does not match /text.txt.

What stupid, simple mistake shall we be held making here? I Researched until I acquired dizzy.

This issue seems to become a consequence of other configuration configurations around the machine under consideration, because the rules will work fine on the vanilla Apache install.