C# gRPC client - name resolution failure

Question

A client is running our C# gRPC client on a corporate network, behind an HTTP proxy. The http_proxy environment variable is configured, but nevertheless he sees an error message Name resolution failure when attempting to connect to the server on the internet.

DNS resolution from the same machine works fine using nslookup.

Any ideas what I can do to investigate this problem?

Answer 1

You can use the following three lines at application startup to configure the detailed logging that @JanTattermusch suggested:

Environment.SetEnvironmentVariable("GRPC_TRACE", "api");
Environment.SetEnvironmentVariable("GRPC_VERBOSITY", "debug");
Grpc.Core.GrpcEnvironment.SetLogger(new Grpc.Core.Logging.ConsoleLogger());

Answer 2

In order to connect a C# gRPC client on a corporate network, behind an HTTP proxy, add this on the client main method works:

Environment.SetEnvironmentVariable("NO_PROXY", "127.0.0.1");