ESXi hosts connected to vCenter Server using NAT disconnect after 30 to 60 seconds

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

• After an ESXi host is added to vCenter Server 5.0, the host disconnects approximately after 30 to 60 seconds
• ESXi 5.0 hosts status shows as disconnected in vCenter Server 30 to 60 seconds after it is added to vCenter Server

Note: In some cases, it may be necessary to manage remote ESXi hosts using vCenter Server. Due to network or ISP limitations it may be necessary to use Network Address Translation (NAT) to connect to vCenter Server. However, even when NAT is configured correctly, you may find that the ESXi hosts keep disconnecting from vCenter Server every 30 to 60 seconds.

Environment

VMware vCenter Server 5.0.x
VMware vSphere ESXi 5.0

Resolution

Using NAT between the vCenter Server system and ESX/ESXi hosts is an unsupported configuration.

vCenter Server requires port 902 UDP for heartbeat functionality. Even when this port is open, the host may still disconnect if the firewall on Windows Server 2008 blocks Edge Traversal.

To resolve this issue, you must enable the Allow Edge Traversal option.

To enable the Allow Edge Traversal option:

1. In Control Panel, open Administrative Tools.
2. Click Windows Firewall with Advanced Security.
3. Click Inbound Rules.
4. Locate and double-click the VMware vCenter Server - Host heartbeat rule.
5. Click the Advanced tab.
6. Select the Allow Edge Traversal option.
7. Click OK.

Note: You need not restart the services for the changes to take effect. However, you may have to remove and readd the ESXi host that was disconnecting.

For related information, see:

• Using NAT between the vCenter Server system and ESX/ESXi hosts (1010652)
• Adding an ESX host to vCenter Server fails with the error: IP Address of the host changed (1035944)