SSP/SSPI: Backup failing with error Error: error creating SFTP connection to server. sftp: sftpConnect: ssh: handshake failed: ssh: unable to authenticate, attempted method

Products

• VMware vDefend Firewall
• VMware vDefend Firewall with Advanced Threat Prevention

Issue/Introduction

SSPI authenticates backup user via public  key while taking backup and SSP/SSPI was unable to authenticate  user via pubic key 

Environment

SSP 5.0 

Cause

SSPI authenticates user via public  key while taking backup and user was unable to authenticate via pubic key 

On the SFTP server, /var/log/secure may show:

 "connection closed by authenticating user 'username' 'ssp-ip' port 34410 [preauth]."

Resolution

Steps to Validate Public Key Authentication

1. Log in to the SSPI CLI.

2. Locate the public key on SSPI at: ~/.ssh/id_rsa.pub

3. Copy the SSPI public key and add it to the ~/.ssh/authorized_keys file on the SFTP server for the intended user.

4. From the SSPI CLI, initiate an SFTP connection using the following command: sftp -i ~/.ssh/id_rsa username@sftpserverip

5. Expected Behavior:

   • The connection should be established without prompting for a password.

   • If no password prompt appears, it confirms successful public key authentication.

 

 Note:

If the command prompts for a password, please try with a different user account that supports key-based login, or investigate and resolve the issue with the current user configuration.