In httpd-2.0, mod_dir uses ap_internal_fast_redirect once it has found an appropriate file from the DirectoryIndex list. This change makes it impossible to use mod_rewrite's proxypass feature on an index file. mod_dir finds the file, but returns its source instead of the output of the proxypass. The fix is to revert mod_dir back to its old behavior, which is to start up an entirely new subrequest once it finds the proper index file.
Created attachment 4059 [details] Fix proxying of index files
I'm going through the bug db to make sure patches are findable. Please see http://httpd.apache.org/dev/patches.html
Also see bug 29961.
Fixed in 2.1 already. http://cvs.apache.org/viewcvs.cgi/httpd-2.0/modules/mappers/mod_dir.c?r1=1.43&r2=1.44 I'm going to propose it for backport.
*** Bug 29961 has been marked as a duplicate of this bug. ***
FYI: the fix will be in 2.0.51.