The sections discussing the available proxies are organized as follows. Overall introduction is followed by proxy class descriptions. Each module has an abstract class which is an interface between the policy and the proxy itself. Abstract classes are the point where the low-level attributes implemented by the proxy appear.

Each Python module contains an abstract proxy class (e.g., AbstractFtpProxy) and one or more preconfigured proxy classes derived from the abstract class (e.g., FtpProxy, FtpProxyRO, etc.). These abstract proxies are very low level classes which always require customization to operate at all, thus they are not directly usable. The preconfigured classes customize the base abstract proxy to perform actually useful functionality. These derived classes inherit all their attributes from the class they were derived from, but have some of their parameters set to default values. Consequently, they can be used for certain tasks without any (or only minimal) modification. Most default classes were derived directly from the abstract classes, but it is possible to derive a class from another derived class. In this case this new class inherits the attributes from its parent class and the abstract class as well. Abstract classes should not be used directly for configuring services in PNS, always derive an own class and modify its attributes to suit the requirements.