Note to be sure to set to 1 (base domains match) and not to 2 (domains match). Otherwise you'll be blocked from many CDNs used by large domains (for example...

Note to be sure to set to 1 (base domains match) and not to 2 (domains match). Otherwise you'll be blocked from many CDNs used by large domains (for example... example.com serves its images and static js from cdn.example.com). Many CDNs are configured to check the referrer to prevent hot-linking of images, javascript, etc. Also note that setting it to 1 will still block you from loading CDN-served images and javascript for smaller sites that are not using their own custom subdomain for their 3rd party CDN service. So, a site using MaxCDN to serve their images and javascript from the default CDN-issued domain of zonename.companyname.netdna-cdn.com with "HTTP Referrer Whitelist" enabled for their example.com domain that you are visiting will block you from downloading images and static javascript hosted on the CDN.