I have an asp.net site and a SharePoint 2010 site. I need to redirect users from my SharePoint site to the asp.net site without asking them for the password again?

  • 1
    Are these Internet, Intranet or Extranet sites?
    – Dave Wise
    Jan 11, 2012 at 14:42
  • Internal? External? NTLM auth? Forms auth? Jan 11, 2012 at 14:42
  • To provide a helpful answer you need to explain your current authentication provider and the authentication used for your ASP.NET site.
    – Russell
    Jan 11, 2012 at 22:40
  • 1
    Sharepoint is doing windows authentication while asp.net app is doing forms
    – RHM
    Jan 12, 2012 at 16:11

4 Answers 4


Configure your ASP.NET web application to use Windows Integrated authentication, just like SharePoint. Furthermore, configure group policies so that the URL where your ASP.NET application is hosted is considered part of the Local Intranet. This will make IE pass the user's credentials to IIS by using Kerberos.

Alternatively, you can configure the ASP.NET application to use Claims, by setting up an STS (ADFS v2). Then configure the STS to use Windows Authentication.


You could use SharePoint's SecureStore to map credentials and pass them to the .NET site.

Another approach is configuring CLAIMs for both SharePoint and your .NET site and relay on the same IdentityProvider (such as ADFS in a Windows environment)


trick way

  • use FQDN to access sp and .net site. e.g. sp.domain.com, web.domain.com
  • write code run in sharepoint to write FBA cookie for current user, domain: domain.com

or you can

  • config asp.net app to use NTLM
  • or
  • config sharepoint to use CBA, and asp.net app use CBA, they use the same STS.
  • +1, I do recommend the classic top level domain name trick. Never had to opportunity to try a common Claim Based Authentication on both SP & custom asp.net solution. As explained in my reply, external solutions are also often dismissed while sometime being already deployed within companies. Nov 25, 2012 at 19:06

I would rely on the same authentication mechanism (eg : ntlm if you're on an intranet) and work with subdomain - as suggested above by Eric - while targeting the cookie to the top level domain name.

Alternatively, you can delegate this requirement to an external tool / system like Microsoft ISA / UAG, SiteMinder, F5 APM, EmpowerID, Oracle Identity Management, ... the biggest advantage is of course compliance with different systems / technologies and the fact that a similar solution might already be in place in your (or your target) environment, waiting for a dedicate configuration to solve this common need.

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