When you want to manage the files of your VMwar ESXi hypervisor, you can use WinSCP without any problem.
However, if you try to connect via SFTP to your VMware vCenter Server (or VCSA) using WinSCP, you will see that this will not work by default.

However, this can be useful, for example, to change the SSL certificate used by default on this server.

1. Encountered problem
2. Fix the problem by configuring WinSCP
3. Change default shell via SSH

1. Encountered problem

You launch WinSCP and attempt to connect to your VMware vCenter Server (or VCSA) via SFTP protocol.

Several windows appear, then an error occurs:

Plain Text

Received unexpected packet in response to authentication request, type 14066632 (unknown).
Authentication log (see session log for details): Using username "root".

VMware vCenter Server Appliance 6.7.0.45100.

2. Fix the problem by configuring WinSCP

Open WinSCP and enter this in the connection window:

• File protocol: SFTP.
• Host name: the domain name or IP address of the VMware vCenter Server (or VCSA).
• Port number: 22
• User name: root.
• Password: his password.

Then, click on the button: Advanced.

In the "Advanced Site Settings" window that appears, go to the section: Environment -> SFTP.

In the "SFTP server" box, specify the value "shell /usr/libexec/sftp-server".
Then, click OK.

Then click the "Save" button.

Indicate under what name you want to save this connection information and the advanced configuration used.
Note that by default, the password will not be saved (unless you check the "Save password (not recommended)" box).

Once the session is saved, click on the button: Login.

Skip the authentication dialog by checking the "Never show this banner again" box and then clicking Continue.

Indicate the password of the "root" account used.

The session starts.

And the connection to your VMware vCenter Server (or VCSA) succeeded.
By default, you will find yourself in the "root" folder (which corresponds to the personal folder of the "root" user).

If you go to the root through the ".." folder, you will see this.

3. Change default shell via SSH

The "Received unexpected packet in response..." error you receive with WinSCP is because the appliancesh defaults to the "root" user instead of the Linux BASH Shell.
You can easily check this by connecting via SSH to your VMware vCenter Server Appliance (VCSA) server.

Once logged in as root, you will see this appear:

Plain Text

Connected to service
    * List APIs: "help api list"
    * List Plugins: "help pi list"
    * Launch BASH: "shell"

Command>

VMware even tells you that to use the BASH Shell, you must first type the "shell" command.

To resolve this issue directly on your VMware vCenter Server Appliance (VCSA) server, simply change the user's default Shell so that the BASH Shell is used by default instead of the "appliancesh".

To do this, access your server's BASH shell by typing:

Bash

shell

Which will display this:

Plain Text

Shell access is granted to root
root@vcsa [ ~ ]#

Next, change the default Shell of the "root" user permanently to BASH Shell:

Bash

chsh -s /bin/bash root

Now, you can connect to your VMware vCenter Server Appliance (VCSA) server using SFTP via WinSCP without getting the error mentioned above.

Once you are done with WinSCP, don't forget to restore the original Shell (VCSA appliance shell):

Bash

chsh -s /bin/appliancesh root

Source : Connecting to vCenter Server Virtual Appliance 6.0 using WinSCP fails with the error: Received too large SFTP packet (2115983).