Im currently thinking about creating a piece of software that will need a Client<->Server<->Client connection, but instead of creating the server software from scratch I was wondering if it would be possible to have it running off a php server. I'm quite new to the world of php and dont quite understand it's full capabilities yet. All i have created so far are pages that are generated by php from accessing my SQL databases and also html page requests. What im wondering is, is it possible to have a client<->client connection through some kind of php software, or have it so that when a client sends a request to a page there will also be a response sent to another client. Im pretty sure this isn't possible, and both clients will just have to keep querying a page to check for any updates since i have no idea how a client could recieve a response without a request in web terms, but i thought i would ask the question none the less.