Return original URL when using reverse proxy

Question

We are using reverse proxy to allow users from outside the firewall to access to services on an internal server. However although we use the ProxyPreserveHost directive, requests with the URL http://project.domain.com/index.html result in http://internal.server/index.html instead of the expected http://project.domain.com/index.html.

Here is our virtual host definition:

<VirtualHost *:443>

        ServerName "https://project.domain.com"
        SSLEngine on
        SSLCertificateFile /etc/ssl/our.cer
        SSLCertificateKeyFile /etc/ssl/private/our.key

        ProxyRequests Off
        ProxyVia Off
        <Proxy *>
            Require all granted
        </Proxy>
        ProxyPreserveHost On
        ProxyPass / http://internal.server:80/
        ProxyPassReverse / http://internal.server:80/

</VirtualHost>

Answer 1

The problem was that the target of the ProxyPass was itself redirected to https://internal.server.

When we changed ProxyPass and ProxyPassReverse target to https://internal.server (bypassing the redirection), the ProxyPreserveHost directive worked.