I need to develop a server side application that opens sockets and manages communication with multiple clients. Previous answers have told me this is possible using a [single script](https://stackoverflow.com/questions/1424511/how-do-scripting-languages-use-sockets/1424517#1424517) file, which [loops forever](https://stackoverflow.com/questions/1427000/what-are-the-ways-to-run-a-server-side-script-forever).

Is this possible using only a PHP/Perl/Python hosting service? or would I need a VPS or [shell access?](http://www.red-pill.eu/freeunix.shtml) 

Any help is appreciated since I've never worked with sockets before. Thanks for your time.