I have a one-way operation that processes requests and can sometimes fail. When the operation fails, the client receives a fault notification. How can I make the operation ignore the bad requests and not send back a fault notification?

This question indicates some confusion over what it means to be a one-way operation. There are actually several different concepts that you could label as one-way.

1. An operation contract with a void return type is one-way in the sense that there is no normal application data to be sent back as part of the operation response.
2. An operation contract declared as IsOneWay is one-way in the sense that execution of the operation does not result in an application message.
3. An operation contract instantiated over a binding offering up IInputChannel is one-way in the sense that there is no path for communicating an operation response back to the client.

As you get further down the list, the definition of one-way becomes more encompassing. The first type of one-way prevents sending normal application data but permits sending an operation response and infrastructure messages. The second type of one-way prevents sending any type of application-level response but permits sending infrastructure messages. The third type of one-way prevents sending any kind of message.

If a fault notification is getting back to the client, then we know that the question is implying the first type of one-way operation. That's the only type that permits returning an exceptional application response. Changing the service to use one of the later types of one-way operations would prevent those fault notifications from being returned.

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