ASP.NET Core | gRPC "Error starting gRPC call: No connection could be made because the target machine actively refused it."

user_9766697 0
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I have a local gRPC client and a remote gRPC server. Local gRPC client is running on IIS. Remote gRPC server runs on Kestrel inside Ubuntu OS. When I'm trying to make a gRPC call from client to server I'm getting RpcException with the following message "Error starting gRPC call: No connection could be made because the target machine actively refused it.".

  • The firewall on the gRPC server machine is disabled.
  • I have successfully intercepted incoming network packages on gRPC server with tcpdump and they seem ok. That means packages are reaching server machine and they are blocked by the application.
  • I can access index page of gRPC server from gRPC client machine using browser.
  • gRPC server Kestrel uses a self-signed SSL certificate.
grpc asp.net-core network-programming c#
1 Answers

I have used port 31700 for gRPC server. Now I changed it to another one, and it works! I will appreciate some explanation of why is this port cannot be used for listening.

user_97666970
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