Connectrix B-Series: How to Troubleshoot an SSH Error when Attempting a Supportsave

A supportsave fails during SSH authentication.

admin> supportsave

This command collects RASLOG, TRACE, supportShow, core file, and then transfer them to a FTP/SCP/SFTP server or a USB dev
This operation can take several minutes.
OK to proceed? (yes, y, no, n) : [no] y

Host IP or Host Name: 10.xx.xx.10
User Name: admin
Remote Directory: /
Protocol (ftp | scp | sftp): sftp
SCP/SFTP Server Port Number [22] : 
Do you want to continue with CRA (Y/N): [N] 
Password:
Saving support information:
SLOT
SWITCH
MODULE
CLI SIZE
CLI TIME
MODULE TIME LOAD AVERAGE
Error occurred in SSH.
Summary worker: 2, cpu load: 3 upload size: 0 KB, time: 1 load:0.3/0.1/0.1
SupportSave completed (upload failure)

Both SCP and SFTP rely on SSH for authentication. SCP essentially uses SSH under the hood to establish a secure connection between the client (switch) and server (for example SANnav or SFTP server) for file transfers.

When you initiate an SCP transfer, there are two authentication steps:

• Server Authentication: SSH uses host keys to authenticate the server.
• User Authentication: In SSH, the client authenticates to the server with a password, key pair, or other methods.

Assuming that your login credentials are correct then the issue is likely caused by a failure during server authentication.

The switch (SSH client) compares the host key presented by the SSH server (10.xx.xx.10) against the keys stored in its known_hosts file. If there is a mismatch, then authentication fails. 

The solution is to clear the erroneous entry from the switch.

Use sshutil delknownhost to clear the SSH (SCP/SFTP) server IP address or hostname from the known hosts table of the device. Only users that have been granted access to use SSH-related tools like sshutil on the Brocade switch can take the following action.

To confirm, use the following command:

sw7:FID128:admin>  sshutil showuser

Should the SCP server connectivity be by any other port than 22 (default SSH) then the port number must also be specified. For example, SSH/SFTP server (10.xx.xx.10:22), use the following syntax:

sw7:FID128:admin> sshutil delknownhost
IP Address/Hostname to be deleted: 10.xx.xx.10

For example, SANnav Server (10.xx.xx.10:6022), use the following syntax:

sw7:FID128:admin> sshutil delknownhost
IP Address/Hostname to be deleted: [10.xx.xx.10]:6022