Proxy caching WordPress with Nginx

I would recommend starting with the Codex Nginx as mentioned by @Rarst. These two additional links may also provide more guidance on what you’re trying to accomplish. How-to: Nginx as a front-end proxy cache for WordPress Nginx Reverse Cache Proxy

Why does defining MULTISITE true change the database connection in use

This sounds like an error with the URLs that are defined in the multisite DB and/or a .htaccess issue. When changing a regular WP install from live to local for example, you can change the URLs by setting this in your wp-config: define(‘WP_HOME’,’http://example.com’); define(‘WP_SITEURL’,’http://example.com’); However with multisite there are additional references to the URLs the … Read more

Rewriting / Redirecting request outside wordpress

Normally, to add rewrite rules in WordPress there is the generate_rewrite_rules filter. From there you can call the function add_external_rule ($wp_rewrite->add_external_rule($rule)) where you could add your rule which not maps to index.php. Unfortunately WordPress will try to write this rule into the .htaccess file. But maybe this could be helpful.