Unable to start a migration from WHM/cPanel: ssh_exchange_identification: Connection closed by remote host

Symptoms

• When starting a migration from WHM/cPanel, the operation fails with:

  [Migration] Failed to detect databases of subscription.
  <...>
  stdout:
  stderr: ssh_exchange_identification: Connection closed by remote host

• An SSH connection from Plesk server to WHM/cPanel server is successful:

  MYSQL_LIN: [[email protected]_server ~]# ssh [email protected]
  Password:
  …
  [[email protected]_server ~]#

Cause

SSHD configuration is not adjusted on the WHM/cPanel server.

Resolution

Adjust the UseDNS and MaxStartups values:

1. Connect to the WHM/cPanel server via SSH.

2. Open the file /etc/ssh/sshd_config file in a text editor. In this example, we are using the vi editor:

   # vi /etc/ssh/sshd_config

3. Make sure these settings do not have a # (hash) character at the beginning of the line and values are the same:

   UseDNS no
   MaxStartups 100:100:1000

4. Save the changes and close the file.

5. Restart the SSH service:

   # service sshd reload