When do I need the Informix native client?

There are two scenarios in which you would require the Informix native client. You must install the Informix client on the same machine as any Informix Single-Tier driver. Additionally, you must install the Informix client on the same machine as OpenLink's Multi-Tier Request Broker and Informix Database Agent, if the Broker and Informix Agent do not reside on the same machine as the Informix database.