WCF Fails Under Load - MessageSecurityException

Question

I am load testing my website. The site calls to a WCF service running on the same box using clientCredentialType="Windows". Everything works until I reach a certain load (which is not even very high), then I get the following error:

System.ServiceModel.Security.MessageSecurityException: The HTTP request was forbidden with client authentication scheme 'Anonymous'. ----> System.Net.WebException: The remote server returned an error: (403) Forbidden.

Upon each call I create a channel:

var proxy = (IClientChannel)channelFactory.CreateChannel();

On success, I close:

proxy.Close();

On error, I abort:

proxy.Abort();

Any ideas what's going on? What I can do to handle loads better? What to look for?

Answer 1

Is your Service a Sessionful Service or do you not worry about keeping state between calls? If you don't have state, you may want to mark your service as a PerCall service. This will make sure that the service instance only exists when a client call is in progress.

Chapter 4 of Juval Lowy's excellent book "Programming WCF Services" 2nd Edition covers this topic.

The default is PerSession which may not be what you want.

Also, see this on MSDN: How To: Control Service Instancing

Answer 2

Thanks Terry. No my service does not maintain state. I tried decorating my service class with:

[ServiceBehaviorAttribute(InstanceContextMode = InstanceContextMode.PerCall)]

No help. The failure point seems to be at about 4 concurrent calls.

Answer 3

The problem was, argh, that I was running the test on my dev box, which is XP, which uses IIS 5, which has a limit of 10 connections.