RA FTP Job fails with error "SSH_MSG_DISCONNECT: 2 Too many authentication failures"

Products

• CA Automic Applications Manager (AM)

Issue/Introduction

When running an RA FTP Job, it may fail with the error "SSH_MSG_DISCONNECT: 2 Too many authentication failures"

The output file may have the below snippets:

****************************************** Start of job log ******************************************

Using SFTP private key file: ~/.ssh/id_ecdsa

Authentications that can continue: publickey
Next authentication method: publickey
PubkeyAcceptedAlgorithms = ssh-ed25519,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,rsa-sha2-512,rsa-sha2-256,ssh-rsa,ssh-dss
PubkeyAcceptedAlgorithms in server-sig-algs = [ssh-ed25519, ecdsa-sha2-nistp256, ecdsa-sha2-nistp384, ecdsa-sha2-nistp521, rsa-sha2-512, rsa-sha2-256, ssh-rsa, ssh-dss]
ecdsa-sha2-nistp521 preauth failure

Disconnecting from remote server hostname port 22

Connection attempt failed: SSH_MSG_DISCONNECT: 2 Too many authentication failures 

ErrorMsg: Internal Error: 1 

Details: SSH_MSG_DISCONNECT: 2 Too many authentication failures 

com.uc4.ftpjob.DataTransferException: Connection exception.

at com.uc4.transfer.CITSFTPImpl.<init>(CITSFTPImpl.java:178)

at com.uc4.ftpjob.connections.ConnectionManager$1.run(ConnectionManager.java:87)

at java.base/java.lang.Thread.run(Unknown Source)

Caused by: com.jcraft.jsch.JSchSessionDisconnectException: SSH_MSG_DISCONNECT: 2 Too many authentication failures 

at com.jcraft.jsch.Session.read(Session.java:1316)

at com.jcraft.jsch.UserAuthPassword.start(UserAuthPassword.java:88)

at com.jcraft.jsch.Session.connect(Session.java:479)

at com.jcraft.jsch.Session.connect(Session.java:198)

at com.uc4.transfer.CITSFTPImpl.connect(CITSFTPImpl.java:232)

at com.uc4.transfer.CITSFTPImpl.openChannel(CITSFTPImpl.java:220)

at com.uc4.transfer.CITSFTPImpl.retryOpenChannel(CITSFTPImpl.java:193)

at com.uc4.transfer.CITSFTPImpl.<init>(CITSFTPImpl.java:164)

... 2 more

 

******************************************* End of job log *******************************************

 

The important points are in bold. 

Using SFTP private key file: ~/.ssh/id_ecdsa --> This line shows that the RA FTP Job's Login object is using a private key for connection authentication

 

Authentications that can continue: publickey
Next authentication method: publickey --> These two lines shows that the RA FTP Job is now checking it's define private key with the remote host's public key. As seen a few lines down, this connection method fails with the message "preauth failure" resulting in the Job failing to connect and end with error "SSH_MSG_DISCONNECT: 2 Too many authentication failures".

Cause

Private/Public key does not match

Resolution

The private key on the source host's (RA FTP Agent server) private key does not match the public key of the remote host.

Refer to the source/remote host's OS administrator to confirm if new keys need to be generated.