Identity provider vs authentication provider

Question

What is the difference between an identity provider and an authentication provider? This is specifically for System Security Services Daemon(SSSD) in Redhat 6/7. I assume the identity provider is like Google or Facebook providing logins to 3rd party website but I'm not sure what an authentication provider does?

Answer 1

The Identity Provider specifies the details of the identity back end to use for the "Security" domain.

The id_provider parameter specifies the type of provider. The common ones are:

• ldap
• ipa (Identity Management in Red Hat Enterprise Linux)
• ad (Microsoft Active Directory)
• proxy, for a legacy NSS provider, such as nss_nis. Using a proxy ID provider also requires specifying the legacy NSS library to load to start successfully, set in the proxy_lib_name option.
• local, the SSSD internal local provider

The Authentication Provider directive specifies the authentication provider used for the domain. If NOT specified, the iIdentity Provider is used. Supported authentication providers are:

• ldap: Native LDAP authentication
• krb5: Kerberos authentication
• proxy: Relays authentication to some other PAM target
• none: Disables authentication explicitly

The best references for SSSD are https://sssd.io/, https://access.redhat.com/ and of course Google.