Network Restore Options in VMware ESXi DCUI

Under Network Restore Options further there are three options :-

1. Restore Network Settings
2. Restore Standard Switch
3. Restore vDS

Recovery is not supported on stateless ESXi instances.

Restore Network Settings

Restoring the network configuration is quite a dangerous option if not used correctly. It has the potential to reset the network to such a state that you will not be able to communicate to the VMware ESX host without resorting to the DCUI to resume communication. It also has the possibility of disconnecting virtual machines (VMs) that are running on the VMware ESX host. Additionally, it has the ability to remove standard and distributed virtual switches (vSwitch) from the host in event that these have become broken on the host beyond repair.

Restore vDS

This option will be greyed out unless your management network is connected to a dvSwitch.You may need to run this if you are having problems with the dvSwitch an this is causing a loss of connectivity to your hosts management network. It may be that you need to fix issues with the dvSwitch, but need to restore host connectivity in the meantime.

The DCUI clones a host local port from the existing misconfigured port and applies the values you provided for VLAN and Blocked. The DCUI changes the Management Network to use the new host local port to restore connectivity to vCenter Server. vCenter Server picks up the new host local port and updates its database with the new information. vCenter Server creates a standalone port that is connected to the Management Network.

Restore Standard Switch

This option will be greyed out unless your management network is connected to a dvSwitch.You may need to run this if you are having problems with the dvSwitch an this is causing a loss of connectivity to your hosts management network. It may be that you need to fix issues with the dvSwitch, but need to restore host connectivity in the meantime.
When you select this option, a new standard vSwitch will be created on the host, with a new vmkernel interface to which an IP can be assigned. An uplink from the dvSwitch will be moved to the new standard vSwitch.

 A vSphere Distributed Switch functions as a single virtual switch across all associated hosts. Virtual machines can maintain a consistent network configuration as they migrate across multiple hosts. If you migrate an existing standard switch, or virtual adapter, to a Distributed Switch and the Distributed Switch becomes unnecessary or stops functioning, you can restore the standard switch to ensure that the host remains accessible.

When you restore the standard switch, a new virtual adapter is created and the management network uplink that is currently connected to Distributed Switch is migrated to the new virtual switch.

You might need to restore the standard switch for the following reasons:

■	The Distributed Switch is not needed or is not functioning.
■	The Distributed Switch needs to be repaired to restore connectivity to vCenter Server and the hosts need to remain accessible.
■	You do not want vCenter Server to manage the host. When the host is not connected to vCenter Server, most Distributed Switch features are unavailable to the host.

Prerequisites

Verify that your management network is connected to a distributed switch.

Procedure

1	From the direct console, select Restore Standard Switch and press Enter. If the host is on a standard switch, this selection is dimmed, and you cannot select it.
2	Press F11 to confirm. Source:- http://buildvirtual.net/utilize-direct-console-user-interface-dcui-and-esxi-shell-to-troubleshoot-configure-and-monitor-esxi-networking/