'Called by L{DNSServerFactory.messageReceived} to decide whether to
process a received message or to reply with C{dns.EREFUSED}.
This default implementation permits anything but empty queries.
Override in a subclass to implement alternative policies.
@param message: The DNS message that was received.
@type message: L{dns.Message}
@param protocol: The DNS protocol instance which received the message
@type protocol: L{dns.DNSDatagramProtocol} or L{dns.DNSProtocol}
@param address: The address from which the message was received. Only
provided for messages received by datagram protocols. The origin of
Messages received from stream protocols can be gleaned from the
protocol C{transport} attribute.
@type address: L{tuple} or L{None}
@return: L{True} if the received message contained one or more queries,
else L{False}.
@rtype: L{bool}'

def allowQuery(self, message, protocol, address):

    return len(message.queries)
