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I have a site1.com which is a Sharepoint site and it uses windows authentication and I have an site2.com asp.net app which uses forms authentication.

I have a link list in sharepoint site which contains a LinkItem to site2.com and when user clicks it... then the prompt is shown from the site2.com to login first and then enter the site. Where as it is needed that ... that site2.com should let the user into the site without asking the login for the second time.

Please tell me how to do it. Requirement is also not to change the authentication methods for the two sites... need to do a workaround that.


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2 Answers 2

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You are using two completely different authentication methods and there is no way around that without building in a 'bypass' on your forms site. In Windows, the user is seen as DOMAIN\JSMITH but on the forms site they are seen as something completely different, usually FORMS\JSMITH. As a human, you see JSMITH in both, but to the software they are 'orange' and 'brick'.

That bypass I refer to is basically a single page on the forms site that is protected by Windows Authentication and it then uses the Windows Auth ID to look up the Forms ID and then force a login for the user on the forms site behind the scenes. This is not advisable but I have seen it done in the past. This will only work if the user ID is the same between site1 and site 2 (i.e. DOMAIN\JSMITH and FORMS\JSMITH) or if a mapping table is used to remap the IDs from one to the other.

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I am going to follow your advice because it looks suitable in the scenario which I have. –  RHM Mar 8 '12 at 17:13
Can you send me some URL's about this approach for a reference. ? –  RHM Mar 8 '12 at 17:14
It has been a while since we used the above solution and it looks like there are some other options. I found two approaches that differ from above but are reasonably well documented 1) mvolo.com/blogs/serverside/archive/2008/02/11/… and 3) msdn.microsoft.com/en-us/library/ms972958.aspx –  Dave Wise Mar 8 '12 at 17:55
I am reading it.. –  RHM Mar 9 '12 at 11:14
This approach will show the windows login popup which I want to skip. For example, if the user is going from sharepoint to the asp.net site then pop up should nt show up instead it should identify the user id and login in programmatically through forms login . –  RHM Mar 9 '12 at 12:29

I believe your Forms authentication is using SQL membership provider. I would suggest a work around which I have found in a post here.

It suggests to have both SQL membership provider and Windows Active Directory Membership provider for Forms authentication. This would enable people with AD authentication to login directly and prompt the login page who come from SQL membership. Its not easy, but possibly achievable.

I would also recommend the Forms authentication application to have AD membership provider to be replaced with SQL membership provider if possible.

Good Luck.

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