I used the Single Sign-on demo from: http://www.codeproject.com/KB/aspnet/SingleSignon.aspx
And I add a SignOut function for this demo, but found a problem:
when I set the cookie.Domain, FormsAuthentication.SignOut() is not working and the cookie can not be cleared.
If the cookie has not been set the cookie.Domain, FormsAuthentication.SignOut() works.
I used C# asp.net.
And could anybody tell me some simple and practical Single Sign-On and Single Sign-Off solutions using asp.net ?
In case you are using the authentication for the same domain and subdomain, try adding the domain name in the web.config instead of adding the domain through code. you will no have to code anything if you use this web.config entry
This entry tells the asp.net engine that the authentication cookie will be used for all subdomains of abc.com . Try using this and see if it works.