Similarly, if you send artifacts, SOAP messages, or provisioning messages to your partner IdP, then you must configure SOAP authentication requirements for receiving SOAP responses, artifact resolution requests, or provisioning requests from your partner.

Back-channel authentication also applies to attribute-request configurations, because this profile always uses the SOAP back channel.

See Configuring back-channel authentication for outbound messages and Configuring back-channel authentication for inbound messages for configuration steps.