We have a couple of customers with enterprise solutions having several sites on different domains. Is it possible to let editors log in once, and stay logged in across all the sites? This is a request from customers using both EPiServer CMS 7 and CMS 6 R2.
Yes, but it depends on the domain names and your setup.
If you use forms authentication you can solve this by changing how the authentication cookie is stored.
Cookies can only be shared across subdomains so it will be easy to fix if you have site1.example.com and site2.example.com to configure the cookie be valid for ".example.com".
If you have www.example.se and www.example.no it is harder but possible by using a admin hostname so you configure iis to bind to se-admin.example.com and no-admin.example.com.
You also need to setup a static machine key in you web.config.