Which is the problem?

An administrator is in the process of deploying a new ESXi host.

-The host is able to be added to the vCenter Server’s inventory, but after a short period of time it shows as disconnected.

-The administrator is able to reconnect the host but it then disconnects again after a short period of time.

Which is the problem?
A . Port 902 UDP from the host to the vCenter Server is blocked
B . Port 443 TCP from the host to the vCenter Server is blocked
C . Port 902 TCP from the host to the vCenter Server is blocked
D . Port 443 TCP from the vCenter Server to the host is blocked

Answer: A

Explanation:

On 902 port managed hosts send a regular heartbeat to the vCenter Server system. This port must not be blocked by firewalls between the server and the hosts or between hosts.