无法通过免费的Azure应用服务连接到远程SFTP服务器

Question

I have a Asp.Net Core website running fine locally I am able to connect to an SFTP server and get files. But once I deploy to Azure app service it will just timeout trying to establish a connection.

The exception I get is

2019-09-03 10:37:28.7942||ERROR|ExclusiveCard.Services.SFTPProvider|Renci.SshNet.Common.SshOperationTimeoutException: Session operation has timed out
   at Renci.SshNet.Session.WaitOnHandle(WaitHandle waitHandle, TimeSpan timeout)
   at Renci.SshNet.Session.WaitOnHandle(WaitHandle waitHandle)
   at Renci.SshNet.Session.Connect()
   at Renci.SshNet.BaseClient.Connect()
   at ExclusiveCard.Services.SFTPProvider.TestConnection() in SFTPProvider.cs:line 237 Renci.SshNet.Common.SshOperationTimeoutException: Session operation has timed out
   at Renci.SshNet.Session.WaitOnHandle(WaitHandle waitHandle, TimeSpan timeout)
   at Renci.SshNet.Session.WaitOnHandle(WaitHandle waitHandle)
   at Renci.SshNet.Session.Connect()
   at Renci.SshNet.BaseClient.Connect()

Code I have used is

SftpClient sftpClient = null;
    try
    {
        sftpClient = new SftpClient("servaer", 2222, "ExclusiveDev", "password");
}
    catch (Renci.SshNet.Common.SshOperationTimeoutException ex)
    {
        Console.WriteLine(ex.ToString());
    }
    catch (Exception e)
    {
        Console.WriteLine(e.ToString());
    }

I have used Package Renci.SshNet.Async version="1.4.0. This code works perfectly fine locally but fails on the Azure App Service when deployed.

Any help much appreciated. Thanks.

Answer 1

It sounds like you have deployed your ASP.NET Core app to Azure App Service on Windows, and it was trying to connect a remote SFTP server from Azure App Service on Windows.

So I'm sure that it will never work fine on Azure App Service of Windows system as you expected, because there is a networking restriction Use of Raw Sockets of Azure Web App sandbox to limit the socket connection establish, as below.

So I suggest you can try to rebuild your app to deploy it to Azure App Service on Linux .