Passing Authentication or REMOTE_USER from One Apache Server to Another

[Kevin Behr <behrk2@xxxxxxxxx>]

Hi there,

I have two separate web applications, each on a different Apache (2.2) server.  A user first authenticates on Server A (either by Basic HTTP or LDAP) and gains access to the web application.  At some point, the user has the option to launch the second web application on Server B.  

The second web application requires REMOTE_USER to be set; it will not start without it.  Therefore, I need the REMOTE_USER from Server A to be passed to Server B.  

I have explored two avenues:

1. Set-up a proxy using mod_proxy_http and leverage the proxy-chain-auth environment variable.
   
   
2. Passing REMOTE_USER via mod_rewrite and RewriteCond.

Am I headed down the right track?  What is the typical way of handling this situation?

I have tried the following httpd.conf configuration on Server A, but it fails to retrieve any REMOTE_USER (which I am accessing via PHP):

ProxyPass /test http://ServerB/

ProxyPassReverse /test http://ServerB/

SetEnv Proxy-Chain-Auth On

I would appreciate any help!