Scanning Network Mac SDK

I have a question. I have a c# application that scans the network开发者_开发知识库 and finds all active IP address on the network. I want to do this in Objective C for a Mac application, does anyone know on how to build a simple network scanner or know of any sample code I could take a look at?

Thanks.

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Apple's Reachability sample may help you, or see the Connection and Reachability APIs.