About IDP-initiated SSO
IDP-initiated SSO occurs when a user attempts to access a protected application, using the IDP for authentication. The IDP sends an unsolicited authentication statement to the SP.
Before IDP-initiated SSO can occur:
- 
The user must access a link on the IDP that refers to the remote SP.
 - 
The user must authenticate to the IDP.
 - 
The IDP must be configured with links that refer to the SP.
 
The following sequence diagram shows the flow of information in IDP-initiated SSO when PingGateway acts as a SAML 2.0 SP: