Service Receives S4U2self KRB_TGS_REP

Services can detect whether the KDC supports S4U by checking the cname of the returned ticket. KDCs that do not support S4U ignore the S4U2self and S4U2proxy data and return a service ticket with the cname containing the name of the service that made the request ([RFC4120] section 3.3.3). In service tickets from KDCs that support S4U, the cname contains the name of the user.