Endpoints in SP Metadata

This page gives guidance and recommendations regarding SAML endpoints in SP metadata. Endpoints in Metadata are crucial to the overall security and interoperability of SAML protocol exchanges.

An endpoint in metadata signals support for a specific profile of SAML. In particular, all SPs in InCommon metadata MUST support SAML2 Web Browser SSO by including certain browser-facing SSO endpoints in metadata. Support for any other profile is strictly OPTIONAL.

Endpoint Requirements

The most important endpoint in SP metadata is the <md:AssertionConsumerService> endpoint. Every SP MUST have at least one such endpoint in metadata.

An SP that supports SAML V2.0 Web Browser SSO MUST include at least one AssertionConsumerService endpoint that supports the SAML V2.0 HTTP-POST binding. Occasionally an IdP will prefer to respond with an artifact, and therefore an AssertionConsumerService endpoint that supports the SAML V2.0 HTTP-Artifact binding MAY also be included in SP metadata. Note: An SP that supports artifact resolution MUST have at least one signing certificate in metadata.

A single topic covering Single Logout Endpoints in both IdP and SP metadata will be found elsewhere in this wiki.

Discovery Service Endpoints in SP Metadata

If your SP is configured to use the SAML V2.0 Identity Provider Discovery Protocol, you MUST configure your SP's metadata to include one or more <idpdisc:DiscoveryResponse> extension elements. (In practice, the actual number of such endpoints is implementation-dependent.) A discovery service will redirect the unauthenticated user back to the SP at the designated endpoint once the user has selected their preferred identity provider.

Technical Details

Support for SAML V2.0 Web Browser SSO is REQUIRED:

<!-- SAML V2.0 -->
<md:AssertionConsumerService index="1" 
    xmlns:md="urn:oasis:names:tc:SAML:2.0:metadata" 
    Binding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST" 
    Location="https://sp.example.org/sso/SAML2/POST"/>
<md:AssertionConsumerService index="2" 
    xmlns:md="urn:oasis:names:tc:SAML:2.0:metadata" 
    Binding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Artifact" 
    Location="https://sp.example.org/sso/SAML2/Artifact"/>

<!-- SAML V2.0 -->
<idpdisc:DiscoveryResponse index="1" 
    xmlns:idpdisc="urn:oasis:names:tc:SAML:profiles:SSO:idp-discovery-protocol" 
    Binding="urn:oasis:names:tc:SAML:profiles:SSO:idp-discovery-protocol" 
    Location="https://sp.example.org/sso/Login"/>

Note that all of the above endpoints are browser-facing endpoints that run on the default SSL/TLS port (443).

Other Issues