After migrating ESXi hosts to new environment, the hosts don't stay connected to vCenter.

Products

• VMware vSphere ESXi

Issue/Introduction

• ESXi hosts have been moved to a new datacenter, and connected to a new vCenter.
• When in Maintenance Mode the hosts blink between connected/disconnected.
• When NOT in Maintenance Mode, the hosts show disconnected.

Environment

vSphere

Cause

Connectivity between the ESXi hosts and vCenter is blocked by a firewall or layer 7 filtering smart switch on ports 902 TCP/UDP, and/or port 443 TCP, which blocks the ability for the heartbeat to be monitored/written to a host.

Resolution

Unblock the ports bidirectionally so that the heartbeat can be correctly monitored.

Additional Information

To get the latest info on which ports are necessary for which features in a VMware product, see the VMware Ports and Protocols page.