I needed to spin up an SFTP server to validate that a backup of our NSX appliance was working, so I tried a couple of free/lightweight SFTP applications that ended up not working (likely because they didn’t support the correct encryption keys/ciphers/algorithms). Dell Support recommends OpenSSH 8.1, so I decided to install the OpenSSH Server that comes with Windows 11.

Install it via. Start > Optional Features > Add > OpenSSH Server

After the installation is complete, validate that the service is running. I believe it is Stopped by default, so start it up.

Services.msc > OpenSSH SSH Server > Start

I then validated that it was working with the following command: ssh localhost -v This command tries to connect to the SSH server and authenticate as the current user. Using -v enables verbose mode, which is helpful for seeing the server host key (fingerprint).
Next, I created a new user account, because I didn’t want to enter my domain user credentials in the NSX backup configuration window, especially during a vendor call. Computer Management > Users > Create

I then tried running an NSX backup, which failed. After checking Windows Firewall (a rule had already been created to allow :22), I decided to edit the SSH Server configuration since it seemed to be listening only via. localhost, not my IP address. Open c:\programdata\ssh\sshd_config and uncomment the #ListenAddress 0.0.0.0 entry, which tells SSH Server to listen on all IPv4 IPs known to the system.
Restart the OpenSSH SSH Server service for the changes to take effect.

Connecting to the IP now worked: ssh 10.1.1.15 -v
I then tried connecting with the new user I’d created: ssh tester@10.1.1.15 -v, which also worked.
Retrying the NSX backup resulted in a successful backup