Subdomain Mapping on (mt)

I have client sites that run on a server (windows based) separate from my blog server (grid-server on mediatemple). So starting off I know there are A records that point to the main server’s IP. My goal is to develop a full proof way of adding a blog to my wp3.0 install if the client’s domain is hosted on any major registrar.

I started reading here http://ottopress.com/2010/wordpress-3-0-multisite-domain-mapping-tutorial/

From that I installed the plugin from the latest trunk, and started playing with a domain and subdomain both on godaddy and both separate domains.

With the domain (not subdomain) I pointed it’s a record to the IP of my blog server, then made changes to match on the WP tools>domain mapping

The subdomain was pointed to the site with a CNAME @ to the wp blog’s subdomain address.

When I do a dig on both it turns up correct, but when I visit the addresses in my browser, both come up white. Seems as if it’s connecting to my gridserver, but not being routed correctly. Any thoughts?