title: Ruby on Rails Single Sign On with multiple enterprise environments
body: <p>Let me start off by saying that I'm not totally sure what I'm looking for. I'm hoping I can explain the situation I'm in, and that someone can point me in the right direction. </p>
  
  <p>So here's what I'm up against. I want to build a ruby on rails application that will be hosted by oranization A on some domain organizationA.com. Then, multiple other organizations (X,Y,Z) will be accessing this tool from other domains (orgx.com, orgy.com, etc.). I do not know at this moment what form of authentication X,Y and Z will use, most likely it will be LDAP or native Windows, but the important thing is that it could be different from organization to organization. </p>
  
  <p>In a situation like this, what is the best way (is there a way?) to allow the users at X,Y and Z to use the application using SSO. Are there any existing tools out there that you would recommend or have worked with? Is there a name for what I'm describing so I can do some better googling?</p>
  
  <p>Any help is much appreciated.</p>
  
  <h1>One Possibility</h1>
  
  <p>CASino - <a href="http://casino.rbcas.com/">http://casino.rbcas.com/</a></p>
  
  <p>Looks like this would be a separate server just for authentication, using the CAS authentication protocol, and could be used for multiple different types of authentication at different organizations. I'll have to check it out.</p>