Sftp connect "The client and the server have no common algorithms."

0 votes
asked Aug 15, 2017 by LinuxSysAdmin (120 points)

We are running Assembly Rebex.Net.Ssh, Version=1.2.2800.0,

and are getting this error when using the attempting to connect to a RHEL 7 server.

[System.Exception: ***** A SftpException has occurred.
Additional Info: Rebex.Net.SftpException: The client and the server have no common algorithms. ---> Rebex.Net.SshException: The client and the server have no common algorithms.
at Rebex.Net.SshSession.Negotiate(Byte[] I_S)

Applies to: Rebex SFTP

1 Answer

0 votes
answered Aug 16, 2017 by Lukas Pokorny (128,250 points)
edited Aug 16, 2017 by Lukas Pokorny

That version of Rebex SFTP has been released 10 years ago and is no longer suitable for use with current SFTP servers. Many servers now require the client to use SSH ciphers that have not even existed in 2007.

Upgrading to the current version should fix the issue. To make sure it works, give the current trial version a try.

If you are interested in details, see the list of currently supported ciphers.

For comparison, this is the list of ciphers we supported in 2007:

Key exchange algorithms: diffie-hellman-group-exchange-sha1, diffie-hellman-group14-sha1, diffie-hellman-group1-sha1
Host key algorithms: ssh-dss, ssh-rsa
Encryption algorithms: aes256-cbc, aes192-cbc, aes128-cbc, 3des-cbc, arcfour128, arcfour, arcfour256, blowfish-cbc, twofish-cbc, twofish256-cbc, twofish192-cbc, twofish128-cbc
MAC algorithms: hmac-md5, hmac-sha1