Check the This computer uses a proxy to access the Internet checkbox if you go online through a proxy.
Fill the boxes with the appropriate values. For example: if your proxy is http://proxy.aol.com:8080 then in the Proxy server box enter http://proxy.aol.com and in the Port box enter 8080
Beginner tip: Don't forget the http:// at the start of the proxy server.
Enter your username into the Proxy username box and enter your password into the Proxy password box.
Prompt for proxy password each time will prompt you for your proxy's password each time you run Plucker Desktop, which is more secure.
Power user tip: If you choose not to prompt each time, then the password will be saved to the configuration file, instead of just located in RAM. Prompting is less convenient, but is more secure.