SAML SSO fails:

My Scenario of authentication is as follows.

1. I have a server name "samlserver", its job is to redirect the request to ID provider for authentication.

2. I have a second server named "accessserver" which redirects every call to "samlserver" for authentication.

3. My implementation logic is as follows:

whenever a request comes for authentication to "samlserver" i store the requested URL against the session ID in a local cache and then set the session id to the cookie as "requestid" before sending the request for authentication. I am setting the cookie so that when the response comes back to the server I can use it to pick the requested URL from the server and redirect the assertion to the respective server, But I am getting my cookie as null in the response, may be it is getting lost due to Post response coming from ID provider from different domain, So just wanted to know is their any workaround to this problem so that each ID provider response is mapped to the correct requested URL.

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Thanks & Regards
Phalguni Mukherjee