Error -4089 EAFNOSUPPORT address family not supported on Azure App Service deployment

[TsengSR]

I am using the rc1-update1 to deploy an application to Azure App Service (free plan for testing).

Using dnx-clr-win-x86.1.0.0-rc1-update1. After deploying I can't connect to the url, it just times out.

Executing web.cmd from the Azure Commandline returns

Microsoft.AspNet.Server.Kestrel.Networking.UvException: Error -4089 EAFNOSUPPORT address family not supported
   at Microsoft.AspNet.Server.Kestrel.Networking.Libuv.Check(Int32 statusCode)
   at Microsoft.AspNet.Server.Kestrel.Networking.Libuv.tcp_bind(UvTcpHandle handle, sockaddr& addr, Int32 flags)
   at Microsoft.AspNet.Server.Kestrel.Networking.UvTcpHandle.Bind(ServerAddress address)
   at Microsoft.AspNet.Server.Kestrel.Http.TcpListener.CreateListenSocket()
   at Microsoft.AspNet.Server.Kestrel.Http.Listener.<>c__DisplayClass5_0.<StartAsync>b__0(Object _)

Not sure what's causing it, I've tried changing the ports of kestrel and just using one url, but nothing helped.

[TsengSR]

Got it. I used http://*:8081 as port. This seems to want to bind IPv6 too which the app service instance do not seem to support. http://0.0.0.0:8081 worked though

[halter73]

Thanks for the report. This does seem like a bug semi-related to #231. If we can't bind to :: (which also binds to 0.0.0.0 if successful), we should try binding to 0.0.0.0 explicitly in UvTcpHandle.Bind.

I'm glad you found a workaround for now.

[mikeharder]

I'm unable to reproduce this in either Azure App Service or self-host.

For Azure App Service, in RC2 the configuration code was changed so UseIISIntegration() overrides UseUrls() (if it is called after). So applications configured with UseUrls("http://*:5000").UseIISIntegration() work fine in App Service, regardless of IPv6.

For self-host, I tested both Windows and Linux, and they allow you to bind to IPv6Any ([::]) even when IPv6 is disabled. So applications configured with UseUrls("http://*:5000") should work fine in Windows and Linux with IPv6 disabled.

CC: @Tratcher, @CesarBS, @halter73

[xavierjohn]

I have got the same error on Azure Web App.
"Error -4089 EAFNOSUPPORT address family not supported"

Here is the startup code

        public static void Main(string[] args)
        {
            var whb = new WebHostBuilder();

            var environment = whb.GetSetting("environment");
            var subjectName = GetCertificateSubjectNameBasedOnEnvironment(environment);
            var certificate = GetServiceCertificate(subjectName);

            var host = whb
                .UseKestrel( options =>
                {
                    var httpsOptions = new HttpsConnectionFilterOptions();
                    httpsOptions.ServerCertificate = certificate;
                    httpsOptions.ClientCertificateMode = ClientCertificateMode.RequireCertificate;
                    httpsOptions.SslProtocols = System.Security.Authentication.SslProtocols.Tls;
                    options.UseHttps(httpsOptions);
                })
                .UseContentRoot(Directory.GetCurrentDirectory())
                .UseUrls("https://*:4430")
                .UseIISIntegration()
                .UseStartup<Startup>()
                .UseApplicationInsights()
                .Build();

            host.Run();
        }