I finally got around to building & testing apache2 as a front-end mod_proxy server for our stuff here at dyn today. Initial testing on our testbed machine is very promising, I just have to run through and re-tweak the configuration (once I acquaint myself with the different ways apache2 does some things) for performance, and then it'll be ready to deploy in production.
Learned that the functionality of the mod_proxy_add_forward module that we'd been using can be accomplished with mod_headers and three RequestHeader rules. Of course, that might be a shade less effecient, since mod_headers is probably bigger than mod_proxy_add_forward, but the latter hasn't been ported to apache2, and the former is in core, and that little bit more memory won't kill us.
