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SpnEndpointIdentity Class

Represents a service principal name (SPN) for an identity when the binding uses Kerberos.

Namespace:  System.ServiceModel
Assembly:  System.ServiceModel (in System.ServiceModel.dll)

public class SpnEndpointIdentity : EndpointIdentity

An SPN is the name by which a client uniquely identifies an instance of a service. If you install multiple instances of a service on computers throughout a forest, each instance must have its own SPN. A given service instance can have multiple SPNs if there are multiple names that clients might use for authentication.

When a client wants to connect to a service, it locates an instance of the service, composes an SPN for that instance, and sets the identity to a SpnEndpointIdentity. A check will be made that the message is intended for that service.

The three authentication modes used under Kerberos are:

  • SSPINegotiate

  • Kerberos

  • KerberosOverTransport.

The following code shows one common way to create an instance of this class.

static EndpointIdentity CreateIdentity()
     WindowsIdentity self = WindowsIdentity.GetCurrent();
     SecurityIdentifier sid = self.User;

     EndpointIdentity identity = null;

     if (sid.IsWellKnown(WellKnownSidType.LocalSystemSid) ||
         sid.IsWellKnown(WellKnownSidType.NetworkServiceSid) ||
         identity = EndpointIdentity.CreateSpnIdentity(
             String.Format(CultureInfo.InvariantCulture, "host/{0}", GetMachineName()));
         // Need an UPN string here
         string domain = GetPrimaryDomain();
         if (domain != null)
             string[] split = self.Name.Split('\\');
             if (split.Length == 2)
                 identity = EndpointIdentity.CreateUpnIdentity(split[1] + "@" + domain);

     return identity;


Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0