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Error while connecting to SFTP

0 votes
by (320 points)

Hi Team,

I am facing an issue with connectivity while connecting to SFTP. Below is the exception stack trace.

We are using the Rebex 3.0.4546.0 version.

Any help in this regard will be greatly appreciated.

Thanks in advance.

Exception Stack Trace:

An existing connection was forcibly closed by the remote host.
Please check transfer mode/ other FTP settings configured in the FTP Servers Form!

Connecting to tf.ftp.citonline.com:22 using Sftp 3.0.4546.0.
15:38:26.608 Info SSH: Negotiation started.
15:38:27.011 Info SSH: Negotiation finished.
15:38:27.013 Info Info: Server: SSH-2.0-N2
15:38:27.015 Info Info: Fingerprint: 8a:6c:9a:e1:03:5b:b9:c4:56:fc:d2:49:88:3e:37:fc
15:38:27.017 Info Info: Cipher info: SSH 2.0, DiffieHellmanGroupExchangeSHA1, RSA, aes256-cbc/aes256-cbc, hmac-sha1/hmac-sha1
15:38:27.131 Info SSH: Received banner: Welcome-N2 
15:38:48.447 Error SSH: System.Net.Sockets.SocketException (0x80004005): An existing connection was forcibly closed by the remote host
   at System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags)
   at Rebex.Net.ProxySocket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags)
   at Rebex.Net.SshSession.1oSQZR(Int32 )
   at Rebex.Net.SshSession.JZ4YLZ(Byte[]& )
   at Rebex.Net.SshSession.1rsOcLZ(1VEj6UZ , Object[] )
   at Rebex.Net.SshSession.2aErfC(OCfHX )
   at Rebex.Net.SshSession.283Jn3()
   at Rebex.Net.SshSession.1QmUCN(String , String , SshPrivateKey , SshGssApiCredentials )
15:38:48.450 Error Info: System.Net.Sockets.SocketException (0x80004005): An existing connection was forcibly closed by the remote host
   at System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags)
   at Rebex.Net.ProxySocket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags)
   at Rebex.Net.SshSession.1oSQZR(Int32 )
   at Rebex.Net.SshSession.JZ4YLZ(Byte[]& )
   at Rebex.Net.SshSession.1rsOcLZ(1VEj6UZ , Object[] )
   at Rebex.Net.SshSession.2aErfC(OCfHX )
   at Rebex.Net.SshSession.283Jn3()
   at Rebex.Net.SshSession.1QmUCN(String , String , SshPrivateKey , SshGssApiCredentials )
   at Rebex.Net.SshSession.Authenticate(String userName, String password, SshPrivateKey privateKey)
   at Rebex.Net.Sftp.Login(String userName, String password, SshPrivateKey privateKey)
15:39:18.735 Info Info: Connecting to tf.ftp.citonline.com:22 using Sftp 3.0.4546.0.
15:39:37.964 Error SSH: Rebex.Net.SshException: The connection was closed by the server. Make sure you are connecting to an SSH or SFTP server.
   at Rebex.Net.SshSession.14Ad4fZ()
   at Rebex.Net.SshSession.Negotiate()
15:39:37.967 Error Info: Rebex.Net.SshException: The connection was closed by the server. Make sure you are connecting to an SSH or SFTP server.
   at Rebex.Net.SshSession.14Ad4fZ()
   at Rebex.Net.SshSession.Negotiate()
   at Rebex.Net.Sftp.Connect(String serverName, Int32 serverPort, SshParameters parameters)

The connection was closed by the server. Make sure you are connecting to an SSH or SFTP server.

Applies to: Rebex SFTP

1 Answer

0 votes
by (72.7k points)

It seems that the problem is caused by your internet connection.

Looking at the log, it can be seen:

  1. It fails randomly. The first try failed in SshSession.Authenticate method, while the second try failed in SshSession.Negotiate method.

  2. It always took around 20 seconds (which is suspicious) before the operation failed.

To ensure that the problem is your internet connection, please try to connect with other tool such as WinSCP or FileZilla.

We tried to connect to the same address "tf.ftp.citonline.com:22" couple of times and we didn't encounter the problem, which corresponds to our hypothesis that the problem is your internet connection.

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