SCP /SFTP job fail with "Common algorithms not found"

Products

• CA Workload Automation DE - Business Agents (dSeries)
• CA Workload Automation DE - System Agent (dSeries)
• Workload Automation Agent
• CA Workload Automation AE - System Agent (AutoSys)

Issue/Introduction

On Workload Automation Agent, the SCP / SFTP job may fail with following errors:

"Common algorithms not found"

If remote server is AIX, then this may happen after a new OpenSSH was applied.

 

Environment

Workload Automation Agent 12.x, v24

OS: Any 

Remote OS: Any

Cause

The error is due to incompatible Public Key algorithm (HostKeyAlgorithms).  As of now, the Workload Agent only supports ssh-rsa and ssh-dss algorithms.  Many new updates to SSH server are disabling these algorithms.

Resolution

Enable the ssh-rsa in the remote server.  Add the following option to the ssh_config, e.g.

HostKeyAlgorithms=ssh-rsa,rsa-sha2-512,rsa-sha2-256
PubkeyAcceptedKeyTypes=+ssh-rsa,ssh-dss

Note: If adding multiple algorithms, then make sure ssh-rsa is first on the list.  For details on how to add the host key, consult your OS manuals.

 

 

Additional Information

AIX users, see this documentation.