loosing Session ID in asp.net in Web Farm

[Sen]

Hi, i have two domains. I am validating the user in www.domain.com and for some page i am redirecting to subdomain.domain.com .I Set the machine key the same and i checked the IIS INSTANCE_META_PATH . When redirect to the subdomain my session is empty. I am using SQL Server state server for storing the session information. In the subdomain request.IsAuthenticated is true. But Session values are empty. Is it because ASP_NET.SessionID cookie is not passed between the servers

I am getting Authentication cookie correctly in Subdomain

Senthil