Is it correct to say that the primary checkbox is only used in conjunction with Redirect Mode?

Also, a site alias entry in the list that is marked as Primary is meaningless if the mode is Canonical. Right?

Can you point me to an information resource that explains the Site Aliases section in some detail? This is a dangerous configuration setting. A wrong configuration here can make a website no longer accessible. I am surprised that the programmers didn't implement robust validation checking to this form.

Daniel

Canonical means that the Primary Alias will be written in the source code of the page in case the site has a second alias and is accessed by that alias. Canonical is just a way to tell Google that they should index the URLs to primary alias.

Redirect means whether or not you want a redirect from an secondary alias to the primary alias.