Question

How to find the Client’s Callback URL for a duplex HTTP binding, from within the service (WCF 3.5)?

Appreciate any help..

Answer 1

To get the callback to the client in a duplex channel what you do is within the method that was invoked on the service you would call

OperationContext.Current.GetCallbackChannel<ICallbackContract>();

where ICallbackContract is replaced with the actual callback contract name.

Edit:
Not sure what you mean by the phrase Clients Callback URL. If you mean the address of the client that could be obtained via:

EndpointAddress clientAddress = OperationContext.Current.Channel.RemoteAddress;