I'm having a problem getting a load balancer to forward connect requests to an instance group in GCP.


I set up instances in an instance group which act as a proxy server. They're running and individually operational (using their own IP addresses, proxy works perfectly)

However when trying to use the instance group with a load balancer (have tried TCP, HTTP2 and HTTP) I get a 405 "The method CONNECT is inappropriate for this URL" for all of them.

Is there something I'm missing? I configured the firewall to accept all traffic (yes, I know this is dumb), set up affinity to route Client IP traffic to a known VM to keep sockets open, etc.



The load balancer is not filtering the requests before sending them to the backend, it just forwards the incoming requests to your backend services.

This response means that the method received in the request-line is known by the origin server but not supported by the target resource alerting the client that the method (verb) is not supported; this is part of an HTTP server's normal operation.1

I would suggest to check if the host url and domains are correctly defined in the web server configuration and the forwarding rule.

Also, this could be related to a misconfiguration of web servers or software components that are supposed to perform the respective action for the desired URL resource. This response may occur with the POST method, which is required for entering data and is blocked for security reasons when accessing HTML documents. Maybe enforcing the method in your service will solve this issue.

To further investigate this issue you will need to provide the more log information. I suppose you discovered these information messages from Stackdriver logging.

  • Hi! Thanks for the response. I figured it was just filtering it, which is why it doesn't make sense. I have the health checks in place for load balancer + instance groups, and they come back positive. The instances in the instance group itself all accept the exact request i'm sending to the load balancer, and work as desired (i'm making a get request with a proxy defined in the request as an agent). So in my mind it has to be something wrong with the load balancer but if it's just forwarding requests that doesn't make sense – apriscott Jun 6 at 14:50
  • If you could solve the issue please let the community know it by providing an answer. If you think my comment was useful, please up vote it. – Lozano Jun 7 at 14:20

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.