NetPen

NetPen is a freeware whiteboard that multiple people can easily draw on and manipulate simultaneously over the network.

Also includes features for teachers such as class voting, and conducting/grading tests (see videos for details).Hosting & Clients

The dialog to the left is used to setup a host or a client and is brought up by clicking on the Connection menu item in the window above. To setup a host click the Hosting checkbox and enter the port to host on. Note that if you're behind a router you may need to setup a NAT translation for the router to forward the data to the port correctly.

To setup a client connection to a host you need to enter the port the host is using and either a URL to the server or the servers IP address.