We are using TCP Google Cloud Loadbalancer for one of our services.
The architecture is the following: There is a TCP load balancer on which a range of ports are allowed on frontend and its backend instances are connected and there instances services are running on same port which is open on LB.
LB IP -220.127.116.11:(100-200) i.e, range of ports are open. Now on backend 3 instances are running and there service are running on port 100, 101 and 103 on them.
As a user, if you want to access the service running on port 100 you have to use LB IP:100 to access the services. But from past few days the request is getting drop. However if you tried to connect directly on instance IP:100 service will work well. hence, I am not able to figure it out the exact cause. The requests are also a TCP based then why LB is dropping it.
Please suggest me with some inputs. Note: Is there any way to check the LB logs from the GCloud or Console ???