Azure WebSite : how to establish a socket connection on loopback interface?

Question

I'm trying to establish a simple socket connection (tcp://localhost:9999) from an Azure WebSite (free). I'm not aware of any restriction about socket usage, so I tried this:

public class TestSocketController : ApiController
{
    public string Get()
    {
        try
        {
            using (var socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
            {
                socket.Connect("localhost", 9999);
                socket.Close();
                return "ok";
            }
        }
        catch (Exception ex)
        {
            return ex.ToString();
        }
    }
}

Which gives the following output:

System.Net.Sockets.SocketException (0x80004005): An attempt was made to access a 
socket in a way forbidden by its access permissions 127.0.0.1:9999   
at System.Net.Sockets.Socket.Connect(IPAddress[] addresses, Int32 port)
at System.Net.Sockets.Socket.Connect(String host, Int32 port)   
at WebApiContainer.Controllers.TestSocketController.Get()

Is there something particular to do to establish a socket connection from a website ? Binding works fine on Azure but Connect doesn't work.

Thanks

See [this blog post](http://azure.microsoft.com/blog/2013/11/14/introduction-to-websockets-on-windows-azure-web-sites/) — Benjamin Gruenbaum, May 02 '15 at 11:54
Yes I enabled websockets event though I think it should make no difference since it is a raw TCP socket, not a web socket. — Eric Boumendil, May 02 '15 at 12:05
I don't think you can open ports in Azure websites, you'd have to use a web role for that. — Benjamin Gruenbaum, May 02 '15 at 12:07
I'm not aware of all the Azure terminology but a WebSite is not it a web role ? — Eric Boumendil, May 02 '15 at 12:11
Yes, it is not. They're different things. Web roles are more powerful but require more work. — Benjamin Gruenbaum, May 02 '15 at 12:15

score 2 · Accepted Answer · edited May 23 '17 at 12:14

2

Thanks to Benjamin's comment, I found this SO answer: it seems not to be possible for an Azure WebSite to establish TCP connection on other than standard ports 80/443, even on the loopback interface.

[Edit: for the record, named pipes do not work either with WebSites.]

So I'm probably stuck with the Service Bus.

edited May 23 '17 at 12:14

Community

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answered May 02 '15 at 12:45

Eric Boumendil

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So did you end up using a web role? – johnnyRose Sep 16 '15 at 16:10
No it's a very little project so I stay with Shared Instances websites. I think the choices I have are: Azure Service Bus (with fees) or a job with periodical checks on file system (or maybe a FileSystemWatcher). – Eric Boumendil Sep 18 '15 at 09:48

Azure WebSite : how to establish a socket connection on loopback interface?

1 Answers1