Unable to negotiate <host> port 22, no matching key exchange / host key algorithm found.

[Shiraj0205]

Getting an error on sshClient.Connect().
Does library supports ssh-dss host key algorithm? Though it supports diffie-hellman-group1-sha1, why i am getting no matching key exchange method found error?

Unable to negotiate with XXXXXX port 22: no matching key exchange method found. Their offer: diffie-hellman-group1-sha1
Unable to negotiate with XXXXXX port 22: no matching host key type found. Their offer: ssh-dss

[SaddamBInSyed]

did you get an answer for this?

Please help

[darkoperator]

Dis you checked the list of supported algorithms in the readme vs what the server is configured with? My guess the server is using Elliptical Curve key that the lib does not support

…

Sent from my iPhone

On Apr 21, 2019, at 7:26 AM, SaddamBinSyed ***@***.***> wrote: did you get an answer for this? Please help — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or mute the thread.

[SaddamBInSyed]

many thanks for your reply.

error message at the server end,

Unable to negotiate with 172.28.102.92 port 53513: no matching host key type found. Their offer: ssh-rsa,ssh-dss [preauth]

please advise,

i am using below code,

var connectionInfo = new ConnectionInfo(host, username, new PasswordAuthenticationMethod(username, password));
connectionInfo.Timeout = new TimeSpan(0, 0, 20); // connection Timeout

using (SftpClient sftpClient = new SftpClient(connectionInfo))
{
sftpClient.HostKeyReceived += SftpClient_HostKeyReceived;
sftpClient.ErrorOccurred += SftpClient_ErrorOccurred;

                Console.WriteLine("Connecting to server");
                sftpClient.Connect();
                Console.WriteLine("connected");
                //using (FileStream fs = new FileStream("filePath", FileMode.Open))
                //{
                //    sftpClient.BufferSize = 1024;
                //    sftpClient.UploadFile(fs, Path.GetFileName("filePath"));
                //}
                sftpClient.Dispose();
            }

[darkoperator]

What is your host key algorithm?

…

Sent from my iPhone

On Apr 21, 2019, at 9:35 AM, SaddamBinSyed ***@***.***> wrote: many thanks for your reply. error message at the server end, Unable to negotiate with 172.28.102.92 port 53513: no matching host key type found. Their offer: ssh-rsa,ssh-dss [preauth] please advise, i am using below code, var connectionInfo = new ConnectionInfo(host, username, new PasswordAuthenticationMethod(username, password)); connectionInfo.Timeout = new TimeSpan(0, 0, 20); // connection Timeout using (SftpClient sftpClient = new SftpClient(connectionInfo)) { sftpClient.HostKeyReceived += SftpClient_HostKeyReceived; sftpClient.ErrorOccurred += SftpClient_ErrorOccurred; Console.WriteLine("Connecting to server"); sftpClient.Connect(); Console.WriteLine("connected"); //using (FileStream fs = new FileStream("filePath", FileMode.Open)) //{ // sftpClient.BufferSize = 1024; // sftpClient.UploadFile(fs, Path.GetFileName("filePath")); //} sftpClient.Dispose(); } — You are receiving this because you commented. Reply to this email directly, view it on GitHub, or mute the thread.

[SaddamBInSyed]

sorry for asking, where can i see that information ( key algorithim)?

[SaddamBInSyed]

When I try to connect with the server then I am getting the below error.

please help.

Renci.SshNet.Common.SshConnectionException: An existing connection was forcibly closed by the remote host ---> System.Net.Sockets.SocketException: 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 Renci.SshNet.Abstractions.SocketAbstraction.Read(Socket socket, Byte[] buffer, Int32 offset, Int32 size, TimeSpan timeout)
at Renci.SshNet.Session.TrySocketRead(Byte[] buffer, Int32 offset, Int32 length)
at Renci.SshNet.Session.ReceiveMessage()
at Renci.SshNet.Session.MessageListener()
--- End of inner exception stack trace ---
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 FtpEngine.ftp.Upload.UploadFilestoSFTPUsingSSH(tb_ftpconfig _configs)

[darkoperator]

At least from the error my guess is that you will have to reconfigure the server to use a key with one of the supported algorithms by the library

…

Sent from my iPhone

On Apr 21, 2019, at 9:35 AM, SaddamBinSyed ***@***.***> wrote: many thanks for your reply. error message at the server end, Unable to negotiate with 172.28.102.92 port 53513: no matching host key type found. Their offer: ssh-rsa,ssh-dss [preauth] please advise, i am using below code, var connectionInfo = new ConnectionInfo(host, username, new PasswordAuthenticationMethod(username, password)); connectionInfo.Timeout = new TimeSpan(0, 0, 20); // connection Timeout using (SftpClient sftpClient = new SftpClient(connectionInfo)) { sftpClient.HostKeyReceived += SftpClient_HostKeyReceived; sftpClient.ErrorOccurred += SftpClient_ErrorOccurred; Console.WriteLine("Connecting to server"); sftpClient.Connect(); Console.WriteLine("connected"); //using (FileStream fs = new FileStream("filePath", FileMode.Open)) //{ // sftpClient.BufferSize = 1024; // sftpClient.UploadFile(fs, Path.GetFileName("filePath")); //} sftpClient.Dispose(); } — You are receiving this because you commented. Reply to this email directly, view it on GitHub, or mute the thread.

[darkoperator]

https://unix.stackexchange.com/questions/223276/how-do-i-list-available-host-key-algorithms-for-an-ssh-client

…

Sent from my iPhone

On Apr 21, 2019, at 9:45 AM, SaddamBinSyed ***@***.***> wrote: When I try to connect with the server then I am getting the below error. please help. Renci.SshNet.Common.SshConnectionException: An existing connection was forcibly closed by the remote host ---> System.Net.Sockets.SocketException: 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 Renci.SshNet.Abstractions.SocketAbstraction.Read(Socket socket, Byte[] buffer, Int32 offset, Int32 size, TimeSpan timeout) at Renci.SshNet.Session.TrySocketRead(Byte[] buffer, Int32 offset, Int32 length) at Renci.SshNet.Session.ReceiveMessage() at Renci.SshNet.Session.MessageListener() --- End of inner exception stack trace --- 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 FtpEngine.ftp.Upload.UploadFilestoSFTPUsingSSH(tb_ftpconfig _configs) — You are receiving this because you commented. Reply to this email directly, view it on GitHub, or mute the thread.

[SaddamBInSyed]

ssh-dss - ssh-rsa

[SaddamBInSyed]

When run the below command i can am getting the following

PS C:\Users\duak5031> ssh -Q key
ssh-ed25519
ssh-ed25519-cert-v01@openssh.com
ssh-rsa
ssh-dss
ecdsa-sha2-nistp256
ecdsa-sha2-nistp384
ecdsa-sha2-nistp521
ssh-rsa-cert-v01@openssh.com
ssh-dss-cert-v01@openssh.com
ecdsa-sha2-nistp256-cert-v01@openssh.com
ecdsa-sha2-nistp384-cert-v01@openssh.com
ecdsa-sha2-nistp521-cert-v01@openssh.com

please advise

[SaddamBInSyed]

At least from the error my guess is that you will have to reconfigure the server to use a key with one of the supported algorithms by the library
…
Sent from my iPhone
On Apr 21, 2019, at 9:35 AM, SaddamBinSyed @.***> wrote: many thanks for your reply. error message at the server end, Unable to negotiate with 172.28.102.92 port 53513: no matching host key type found. Their offer: ssh-rsa,ssh-dss [preauth] please advise, i am using below code, var connectionInfo = new ConnectionInfo(host, username, new PasswordAuthenticationMethod(username, password)); connectionInfo.Timeout = new TimeSpan(0, 0, 20); // connection Timeout using (SftpClient sftpClient = new SftpClient(connectionInfo)) { sftpClient.HostKeyReceived += SftpClient_HostKeyReceived; sftpClient.ErrorOccurred += SftpClient_ErrorOccurred; Console.WriteLine("Connecting to server"); sftpClient.Connect(); Console.WriteLine("connected"); //using (FileStream fs = new FileStream("filePath", FileMode.Open)) //{ // sftpClient.BufferSize = 1024; // sftpClient.UploadFile(fs, Path.GetFileName("filePath")); //} sftpClient.Dispose(); } — You are receiving this because you commented. Reply to this email directly, view it on GitHub, or mute the thread.

So what I understood is, we need to add the library supported key algorithm in to SFTP server config files?
Is it so??

please help

[SaddamBInSyed]

I have added below config to the sshconfig file

HostKeyAlgorithms +ssh-rsa,ssh-dss
KexAlgorithms +diffie-hellman-group1-sha1

[drieseng]

In the next beta, we'll add support for the following key exchange algorithms:

• curve25519-sha256
• curve25519-sha256@libssh.org
• ecdh-sha2-nistp256
• ecdh-sha2-nistp384
• ecdh-sha2-nistp521
• diffie-hellman-group14-sha256
• diffie-hellman-group16-sha512

and we've added support for the following host key algorithms:

• ssh-ed25519
• ecdsa-sha2-nistp256
• ecdsa-sha2-nistp384
• ecdsa-sha2-nistp521

[drieseng]

2020.0.0-beta1 is now available.