I am trying to right a Google Cloud Platform app in python with Flask that makes an MQTT connection. I have included the paho python library by doing pip install paho-mqtt -t libs/. However, when I try to run the app, even if I don't try to connect to MQTT. I get a weird error about IP address checking: RuntimeError: error('illegal IP address string passed to inet_pton',) It seems something in the remote_socket lib is causing a problem. Is this a security issue? Is there someway to disable it? Relevant code: from flask import Flask import paho.mqtt.client as mqtt import logging as logger app = Flask(__name__) # Note: We don't need to call run() since our application is embedded within # the App Engine WSGI application server. #callback to print out connection status def on_connect(mosq, obj, rc): logger.info('on_connect') if rc == 0: logger.info("Connected") mqttc.subscribe('test', 0) else: logger.info(rc) def on_message(mqttc, obj, msg): logger.info(msg.topic+" "+str(msg.qos)+" "+str(msg.payload)) mqttc = mqtt.Client("mqttpy") mqttc.on_message = on_message mqttc.on_connect = on_connect As well as full stack trace: ERROR 2014-06-03 15:14:57,285 wsgi.py:262] Traceback (most recent call last): File "/Users/cbarnes/google-cloud-sdk/platform/google_appengine/google/appengine/runtime/wsgi.py", line 239, in Handle handler = _config_handle.add_wsgi_middleware(self._LoadHandler()) File "/Users/cbarnes/google-cloud-sdk/platform/google_appengine/google/appengine/runtime/wsgi.py", line 298, in _LoadHandler handler, path, err = LoadObject(self._handler) File "/Users/cbarnes/google-cloud-sdk/platform/google_appengine/google/appengine/runtime/wsgi.py", line 84, in LoadObject obj = __import__(path[0]) File "/Users/cbarnes/code/ignite/tank-demo/appengine-flask-demo/main.py", line 24, in <module> mqttc = mqtt.Client("mqtthtpp") File "/Users/cbarnes/code/ignite/tank-demo/appengine-flask-demo/lib/paho/mqtt/client.py", line 403, in __init__ self._sockpairR, self._sockpairW = _socketpair_compat() File "/Users/cbarnes/code/ignite/tank-demo/appengine-flask-demo/lib/paho/mqtt/client.py", line 255, in _socketpair_compat listensock.bind(("localhost", 0)) File "/Users/cbarnes/google-cloud-sdk/platform/google_appengine/google/appengine/dist27/socket.py", line 222, in meth return getattr(self._sock,name)(*args) File "/Users/cbarnes/google-cloud-sdk/platform/google_appengine/google/appengine/api/remote_socket/_remote_socket.py", line 668, in bind self._SetProtoFromAddr(request.mutable_proxy_external_ip(), address) File "/Users/cbarnes/google-cloud-sdk/platform/google_appengine/google/appengine/api/remote_socket/_remote_socket.py", line 632, in _SetProtoFromAddr proto.set_packed_address(self._GetPackedAddr(address)) File "/Users/cbarnes/google-cloud-sdk/platform/google_appengine/google/appengine/api/remote_socket/_remote_socket.py", line 627, in _GetPackedAddr AI_NUMERICSERV|AI_PASSIVE): File "/Users/cbarnes/google-cloud-sdk/platform/google_appengine/google/appengine/api/remote_socket/_remote_socket.py", line 338, in getaddrinfo canonical=(flags & AI_CANONNAME)) File "/Users/cbarnes/google-cloud-sdk/platform/google_appengine/google/appengine/api/remote_socket/_remote_socket.py", line 211, in _Resolve canon, aliases, addresses = _ResolveName(name, families) File "/Users/cbarnes/google-cloud-sdk/platform/google_appengine/google/appengine/api/remote_socket/_remote_socket.py", line 229, in _ResolveName apiproxy_stub_map.MakeSyncCall('remote_socket', 'Resolve', request, reply) File "/Users/cbarnes/google-cloud-sdk/platform/google_appengine/google/appengine/api/apiproxy_stub_map.py", line 94, in MakeSyncCall return stubmap.MakeSyncCall(service, call, request, response) File "/Users/cbarnes/google-cloud-sdk/platform/google_appengine/google/appengine/api/apiproxy_stub_map.py", line 328, in MakeSyncCall rpc.CheckSuccess() File "/Users/cbarnes/google-cloud-sdk/platform/google_appengine/google/appengine/api/apiproxy_rpc.py", line 156, in _WaitImpl self.request, self.response) File "/Users/cbarnes/google-cloud-sdk/platform/google_appengine/google/appengine/ext/remote_api/remote_api_stub.py", line 200, in MakeSyncCall self._MakeRealSyncCall(service, call, request, response) File "/Users/cbarnes/google-cloud-sdk/platform/google_appengine/google/appengine/ext/remote_api/remote_api_stub.py", line 234, in _MakeRealSyncCall raise pickle.loads(response_pb.exception()) RuntimeError: error('illegal IP address string passed to inet_pton',) INFO 2014-06-03 15:14:57,291 module.py:639] default: "GET / HTTP/1.1" 500 - Thanks!