Finding the Relying Party Trust Identifier for a SharePoint ADFS server
Some federation environments use multiple ADFS servers to authenticate users in SharePoint. In these environments, a trust is established between SharePoint and an ADFS server, and another trust between this ADFS server and another ADFS server. Configurations using multiple ADFS servers can be used, for example, when federating users from different Active Directory domains.
In order for the Claims security provider to be able to authenticate to SharePoint web applications using such a configuration, information from both ADFS servers is required.
To find the Relying Party Trust identifier for your SharePoint ADFS server
Log on to the ADFS server which is trusted by the SharePoint ADFS server.
Access AD FS 2.0 Management Console (Windows Start menu > All Programs > Administrative Tools > AD FS 2.0 Management.
In AD FS 2.0 Management Console, under Trust Relationships, select Relying Party Trusts.
In the list of trusts displayed, find the trust for the ADFS server which is trusted by SharePoint. The ADFS Relying Party Identifier will be the value in the Identifier column.