I have www.telscenter.org/confluence[1] operating as a proxy for tels-group.soe.berkeley.edu:9006/confluence[2], which is a Tomcat appserver. Here's the relevant snip of httpd.conf:

1. Atlassian Confluence
   ProxyPass /confluence/ http://tels-group.soe.berkeley.edu:9006/confluence/
   ProxyPassReverse /confluence/ http://tels-group.soe.berkeley.edu:9006/confluence/

I go to [1] and log in. It succeeds but redirects me to [2]. I can return to [1] and I will be logged in, but my users don't know to do this. I've recorded the HTTP session and I see that Confluence is redirecting on successful login, which makes sense, but I would expect to observe my "Server Base URL" configuration which is "http://www.telscenter.org/confluence/".

FWIW, changing "Site Homepage" has no effect. Incidentally, when I choose "dashboard" the option shows up blank.

Attached is the capture from Firefox's "Live HTTP headers" extension.