An Identity Provider (IdP) in Salesforce allows you to configure your Salesforce instance as the provider of user authentication and validation for other applications. This means that if a user is successfully authenticated and validated by your Salesforce instance, they will also be granted access to other applications that utilize the IdP service.
An Auth Provider in Salesforce is a configuration that allows you to specify other external Identity Providers (IdPs) that are authorized to authenticate users to log in to your Salesforce instance. For example, if you set up Google as an Auth Provider, Salesforce will consider a user to be a legitimate user if they are successfully authenticated by Google. In this scenario, Salesforce acts as a Service Provider (SP). Salesforce has predefined Auth connectors that are built on OpenID, which can be used to connect to popular third-party IdPs like Facebook, LinkedIn, and Google. Additionally, if the IdP supports OpenID or OAUTH 2.0, you can define your own Auth Provider.
The SSO Settings in Salesforce allows you to configure your instance of Salesforce as a Service Provider (SP) for Single Sign-On (SSO) using the SAML authentication method. This setup involves configuring your Salesforce instance with information from the Identity Provider (IdP), which acts as the gatekeeper for user access to other organizations in a multi-org Salesforce environment. Additionally, the Just-In-Time (JIT) provisioning feature in SSO Settings enables the creation or updating of users in your Salesforce instance when they are authenticated by external systems. The registration handler in Auth Providers can also be used for JIT user provisioning when users are authenticated by external systems.
A Connected App in Salesforce allows external systems to connect to your instance for identity and resource access. It acts as a bridge for external systems to access the resources they need, and can be used for both Identity Provider and Service Provider functionality. The Connected App also includes a user provisioning wizard to manage user events such as creation, activation, and updates in other connected applications.
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