Which software is right?

[Peter Schober]

* Constance   Morris <cmorris at daltonstate.edu> [2013-04-08 14:56]:
> We currently use Active Directory (AD) over our LDAP for
> authentication. However, we need for our clients to be able to SSO
> into our portal and be able to access all resources within from that
> initial login authentication. I've been considered CAS, but came
> across Shibboleth.net and thought I would give it a try.
[...]
> Also, which is the preferred OS to use....Linux or Windows (we have
> both)?

More specifically, the OS for the Service Provider will be dictated by
your current portal, as the SP ideally will run on that same machine.

If you need to access the portal via SAML for your own users (instead
of having two seperate protocols for interal vs. external subjects),
for example for off-site access (assuming your MS-Active Directory is
not an option there) you'd also needed to install and configure a SAML
IdP.
Given that the IdP is in Java I'd recommend a platform which provides
security fixes for the JVM in a timely matter.
-peter