This policy setting applies to applications using the Cred SSP component (for example: Remote Desktop Connection). This policy ...

This policy setting applies to applications using the Cred SSP component (for example: Remote Desktop Connection).

This policy setting applies when server authentication was achieved by using a trusted X509 certificate or Kerberos.

If you enable this policy setting, you can specify the servers to which the user's default credentials can be delegated (default credentials are those that you use when first logging on to Windows).

The policy becomes effective the next time the user signs on to a computer running Windows.

If you disable or do not configure (by default) this policy setting, delegation of default credentials is not permitted to any computer. Applications depending upon this delegation behavior might fail authentication. For more information, see KB.

FWlink for KB:
http://go.microsoft.com/fwlink/?LinkId=301508

Note: The "Allow delegating default credentials" policy setting can be set to one or more Service Principal Names (SPNs).  The SPN represents the target server to which the user credentials can be delegated.  The use of a single wildcard character is permitted when specifying the SPN.

For Example:
TERMSRV/host.humanresources.fabrikam.com Remote Desktop Session Host running on host.humanresources.fabrikam.com machine
TERMSRV/* Remote Desktop Session Host running on all machines.
TERMSRV/*.humanresources.fabrikam.com Remote Desktop Session Host running on all machines in .humanresources.fabrikam.com