You can use SSH to remotely log in to the ESXi Shell and perform troubleshooting tasks for the host.

SSH configuration in ESXi is enhanced to provide a high security level.

Version 1 SSH protocol disabled
VMware does not support Version 1 SSH protocol and uses Version 2 protocol exclusively. Version 2 eliminates certain security problems present in Version 1 and provides you with a safe way to communicate with the management interface.
Improved cipher strength
SSH supports only 256-bit and 128-bit AES ciphers for your connections.

These settings are designed to provide solid protection for the data you transmit to the management interface through SSH. You cannot change these settings.