title: gRPC on localhost refuses connection when app in docker on WSL2 tries to connect to
body: <p>I have wsl2 installed and docker desktop for windows on Windows 10.
  There is some strange behavior with gRPC server.</p>
  <p>Each time I'm making request to  my gRPC server (on WSL2) inside a docker container I got
  connection refused error. I can do simple checking like this:</p>
  <pre><code>curl -v host.docker.internal:50051
  *   Trying 192.168.65.2:50051...
  * connect to 192.168.65.2 port 50051 failed: Connection refused
  * Failed to connect to host.docker.internal port 50051: Connection refused
  * Closing connection 0
  curl: (7) Failed to connect to host.docker.internal port 50051: Connection refused
  </code></pre>
  <p>Any other non-grpc app works fine! Or even same grpc but on windows side.</p>
  <p>Simple nodejs app on WSL2:</p>
  <pre><code>curl -v host.docker.internal:3000
  *   Trying 192.168.65.2:3000...
  * Connected to host.docker.internal (192.168.65.2) port 3000 (#0)
  &gt; GET / HTTP/1.1
  &gt; Host: host.docker.internal:3000
  &gt; User-Agent: curl/7.69.1
  &gt; Accept: */*
  &gt;
  * Mark bundle as not supporting multiuse
  &lt; HTTP/1.1 200 OK
  &lt; Date: Mon, 29 Jun 2020 10:22:15 GMT
  &lt; Connection: keep-alive
  &lt; Transfer-Encoding: chunked
  &lt;
  * Connection #0 to host host.docker.internal left intact
  Hello, World!
  </code></pre>
  <p>Grpc server on windows side:</p>
  <pre><code>curl -v host.docker.internal:50051
  *   Trying 192.168.65.2:50051...
  * TCP_NODELAY set
  * Connected to host.docker.internal (192.168.65.2) port 50051 (#0)
  &gt; GET / HTTP/1.1
  &gt; Host: host.docker.internal:50051
  &gt; User-Agent: curl/7.66.0
  &gt; Accept: */*
  &gt;
  * Received HTTP/0.9 when not allowed
  
  * Closing connection 0
  curl: (1) Received HTTP/0.9 when not allowed
  </code></pre>