403 error after installing Mongrel with Apache2

If you’ve installed Mongrel for your Rails application with Apache2 as a proxy and receive 403-Forbidden error, first look in apache error log. If you have something like

[warn] proxy: No protocol handler was valid for the URL. If you are using a DSO version of mod_proxy, make sure the proxy submodules are included in the configuration using LoadModule.

you probably forgot to enable/load all required modules. Make sure you have proxy, proxy_balancer and proxy_http.

Tuesday, November 13th, 2007