SftpClient.ConnectAsync hangs

[timurposhva]

Hi!

When connecting to the sftp server, the method SftpClient.ConnectAsync hangs(timeout not working).

My configuration:
Timeout: 60s
OperationTimeout: 10s

OS: windows server 2019
SSH.NET version: 2024.0.0
NET version: 8.0

Stack trace:

System.OperationCanceledException: The operation was canceled. at System.Threading.CancellationToken.ThrowOperationCanceledException() at System.Threading.CancellationToken.ThrowIfCancellationRequested() at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.ThrowException(SocketError error, CancellationToken cancellationToken) at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.System.Threading.Tasks.Sources.IValueTaskSource<System.Int32>.GetResult(Int16 token) at Renci.SshNet.Connection.ProtocolVersionExchange.SocketReadLineAsync(Socket socket, List1 buffer, CancellationToken cancellationToken) at Renci.SshNet.Connection.ProtocolVersionExchange.StartAsync(String clientVersion, Socket socket, CancellationToken cancellationToken) at Renci.SshNet.Session.ConnectAsync(CancellationToken cancellationToken) at Renci.SshNet.BaseClient.CreateAndConnectSessionAsync(CancellationToken cancellationToken) at Renci.SshNet.BaseClient.ConnectAsync(CancellationToken cancellationToken)

Thank you in advance!

[Rob-Hague]

Looks like the very initial protocol handshake is timing out. Are you able to connect to this server with any other SFTP client e.g. WinSCP?

[timurposhva]

Looks like the very initial protocol handshake is timing out. Are you able to connect to this server with any other SFTP client e.g. WinSCP?

I can connect using SSH.NET or WinSCP. But the SSH.NET stops responding from time to time. The synchronous version SftpClient.Connect works fine.

[Rob-Hague]

So do you mean that both Connect and ConnectAsync do not successfully connect, but Connect respects ConnectionInfo.Timeout while ConnectAsync doesn't, or that Connect() connects successfully but ConnectAsync() doesn't?

[timurposhva]

Connect respects ConnectionInfo.Timeout while ConnectAsync doesn't?

correct

[djfoxer]

Yup, I had excalty same issue. ConnectAsync never ends but Connect ends (with fail message) after ConnectionInfo.Timeout seconds.