[horde] horde + apache 2.2.x + mod_proxy?

[Liam Hoekenga]

So... since we installed 3.2, the load on our servers is significantly higher.
Kevin's made some very helpful suggestions as to the use of openBSD's  
PF and CARP.. but ideally I'd like a solution that wouldn't involve a  
new OS.

I'm looking at mod_proxy and mod_proxy_balancer as a possible  
solution.. but I've not got it working.

Every time I hit the front end, the browser is redirected to backend,  
and the user sees the backend's IP address.

My front end conf looks like this..

     ProxyPass / balancer://webmail/
     ProxyPassReverse / balancer://webmail/
     SSLProxyEngine      on
     <Proxy balancer://webmail>
         BalancerMember https://xxx.xxx.xxx.xxx
     </Proxy>

I found a suggestion in some old mail via marc, that I might want to  
add some stuff to horde/config/conf.php, so the horde installation on  
the backend server had information for the front end.

     $conf['server']['name'] = 'web-test.mail.umich.edu';
     $conf['cookie']['domain'] = 'web-test.mail.umich.edu';


I can access our cache statistics and cgi on the backend via the front  
end, and the URL never changes in the browser... but as soon as I  
point it at horde, the IP address of the backend server is revealed to  
the user (shown in the browser's location bar)/

Anyone have suggestions?

Liam