UdpClient receives packets to 127.0.0.1 but fails to get them for interface IP address

Question

I have a strange issue when the packets sent to loopback interface are received successfully, but the same packets sent to the local network interface are lost and never received:

let test (local:IPEndPoint) =
    Async.Parallel [
        async {
            use client = new UdpClient()
            client.ExclusiveAddressUse <- false
            client.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true)
            client.Client.Bind(local);

            printfn "Listen: %A" local.Address

            while true do
                let mutable remote = local
                client.Receive(&remote) |> ignore
                printfn "%A: %A" local.Address remote.Address
        };
        async {
            while true do
                do! Async.Sleep 500

                use senderUC = new UdpClient()
                senderUC.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true)
                senderUC.Send([|byte(1)|], 1, local) |> ignore

                printfn "sent to %A" local
        }
    ] |> Async.RunSynchronously

// this one works
test(new IPEndPoint(IPAddress.Parse("127.0.0.1"), 5353)) |> ignore

// this one does not
//test(new IPEndPoint(IPAddress.Parse("10.211.55.3"), 5353)) |> ignore

ipconfig:

C:\Users\Alex>ipconfig

Windows IP Configuration

Ethernet adapter vEthernet (Intel(R) PRO 1000 MT Network Connection Virtual Switch):

   Connection-specific DNS Suffix  . : localdomain
   IPv4 Address. . . . . . . . . . . : 10.211.55.3
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . : 10.211.55.1

Wireshark shows the packets sending (after re-routing to the default gateway).

Windows firewall is turned off.

I have no idea what to test...

Answer 1

Well, 5353 is Apple Bonjour service (Zeroconf). So while Bonjour is running it captures these datagrams before they reach the client. Disabling it in Services pumps the packet to my app.