Most of the time JBS will detect your web connection automatically, but sometimes you might have some strange configuration it can't handle.
With this page you can specify how John's Background Switcher connects to the internet. You only need to use this option if the default settings don't work - you may need to specify different proxy settings than your login credentials. To do this click the 'Use the following proxy' radio box and fill in the values marked below (clicking the Test button to be sure you've entered them correctly).