session variables not carrying over from http://www.xxxx.com to http://xxxx.com

I was brought aware of this issue by s开发者_Go百科ome users on my website. A user many enter into their browser http://xxxx.com and then login. Then they may click on a link that brings them to http://www.xxxx.com it asks them to login again! Is this a known issue that anyone has encountered before? I tried googling it but im not sure if im using the wrong keywords or what because i cannot find anything related to this.

Thanks, Ian McCullough

As far as your browser is concerned, www.xxxx.com and xxxx.com are different domains. The same-origin policy prevents accessing cookies across domains.

However, the browser is aware of subdomains, and a subdomain can access the cookies of a parent domain. So, if you want to make your cookie accessible to both xxxx.com and www.xxxx.com, just set your cookie on .xxxx.com and you'll be set.

When you set a cookie, you can optionally specify which domain the cookie is set for. If you don't, the cookie is particular to that hostname only, and thus if the cookie is set on www.example.com, it will only be returned by the browser on that hostname or below.

If, when setting the cookie, you set the domain to "example.com" it should work also on "www.example.com".

The problem is that the more specific cookie will override the less specific one, so if you've previously set a cookie on "www.example.com" it will continue to override the new one set for "example.com", rather than being replaced by it - you would first have to delete the one set for "www.example.com". It gets tricky since when the client returns a cookie to the server it doesn't say which hostname the cookie was set for.

People seem to be assuming you're using a cookie to perform authentication but are skipping what appears to be your root question. Trevor briefly touched on it, but still kept to the cookie concept. As far as http is concerned, www.xxxx.com and xxxx.com are different subdomains on the same top level domain. Hence, while they may be the same ip, same website, same everything, the browser request and the server's response are considered to be 2 separate domains/sites. Sessions are not shared across subdomains unless you have a separated session state (such as a SQL Session store, etc).

However, if you are using cookies for authentication, you can add a check for the cookie and rebuild a fresh session if the data in the cookie is valid (and sufficient to reconstruct session). Otherwise you'll have to separate session state from the process into a data store.

Check the domain of the cookie, when creating a cookie you can specify if it is for all sub domains, the root server, specific sub domain, etc. To handle all, the cookie would be for .example.com