BAS-o-matic allows you to capture traffic on the loopback interface. To start monitoring the loopback interface, select it from the drop-down list in the toolbar.
Loopback packets are the packets sent/received within the same computer, i.e. self-addressed packets. Typically, there is virtually no loopback traffic on the standard PC. However, loopback traffic is widely used by software developers for debugging network-related applications. Therefore, BAS-o-matic's loopback-capturing functionality is targeted primarily at this user group.