'Called when a valid query is received to look up and deliver the
response.
@param portOnServer: The server port from the query.
@param portOnClient: The client port from the query.'

def validQuery(self, portOnServer, portOnClient):

    serverAddr = (self.transport.getHost().host, portOnServer)
    clientAddr = (self.transport.getPeer().host, portOnClient)
    defer.maybeDeferred(self.lookup, serverAddr, clientAddr).addCallback(self._cbLookup, portOnServer, portOnClient).addErrback(self._ebLookup, portOnServer, portOnClient)
