This attribute allows sharing of the anonymous identification cookie across domains that have a common DNS namespace (for example, all sites that end in "contoso.com"). The following requirements must be met in order for anonymous identification cookies to be shared:

• Sites that want to share the cookie need to have common decryption and validation keys.

• Other anonymous identification configuration attributes such as cookie path and cookie name must be the same for all the sites.

For more information, refer to the System.Web.HttpCookie class.