When performing a file-based backup of vCenter, the target SFTP server reports the error: "refusing non-sftp session."

Products

• VMware vCenter Server

Issue/Introduction

• The file-based backup completes successfully.
• However, the following message is reported on the destination SFTP server: refusing non-sftp session

Cause

For SFTP backups, vCenter attempts to establish an SSH tunnel for faster performance. If the tunnel creation fails, the backup process falls back to using curl commands.
Therefore, if the SFTP server does not permit SSH connections, it is expected that a message such as "refusing non-sftp session" will be generated each time a backup is performed.

This situation typically originates from the SSH server configuration (sshd_config) on the backup server.

In following example, SSH connections will be denied for users belonging to the "sftponly" group.

Match Group sftponly
    ChrootDirectory %h
    ForceCommand internal-sftp

Resolution

Consider one of the following options:

• Ignore the error on the SFTP server.
• Modify the SFTP server configuration to allow SSH connections.

Additional Information

Japanese KB: vCenterのファイルベースのバックアップを実行すると、ターゲットのSFTPサーバーから"refusing non-sftp session."というエラーが報告される