If you do not specify a host/port pair, then the module defaults to using www.google.com on port 80.
You may optionally specify the port by its name, as in http or ldap. If you do this, the test module will attempt to look up the port number using getservbyname.
If you do specify a host and port, they must be specified in pairs. It is a fatal error to omit one or the other.
If the environment variable NO_NETWORK_TESTING is set, then the tests will be skipped without attempting any socket connections.
If the sockets cannot connect to the specified hosts and ports, the exception is caught, reported and the tests skipped.