is there socket.so file?

Hi there, I'm currently writing an IRC bot using php (CLI) and get a little problem. For windows version, I need to enable socket extension (socket.dll) and my bot will be able to connect to an IRC server. But in linux version, it's unable to connect. So I wonder if there's a " socket.so" or something else to activate socket extension. And the question is, do I need socket extension in Linux? -- regards, Yeni Setiawan