Error: Wake-on-LAN (WOL) fails for virtual machines on NSX-T Subnets

Products

• VMware NSX

Issue/Introduction

Users are unable to power on virtual machines (VMs) located on NSX-T logical segments using Wake-on-LAN (WOL) magic packets sent from different subnets or physical networks. This issue typically occurs because standard broadcast packets do not cross Layer 3 boundaries (Tier-1 or Tier-0 Gateways) without specific directed broadcast configurations.

Environment

• ESXi 8.x
• NSX 4.x

Cause

Wake-on-LAN relies on Layer 2 broadcast packets. By default, NSX-T Gateways and physical routers do not forward these broadcasts across routed segments unless configured for IP directed-broadcast.

Resolution

Follow these steps to enable WOL for virtual machines behind an NSX-T subnet:

1. Verify the ESXi host NIC supports WOL by running the following command in the ESXi CLI: esxcli network nic set -n #### -w g
2. Change the VM Network Adapter type to VMXNET3.
3. Right-click the VM, select Edit Settings > VM Options > Power Management, and ensure Wake on LAN is selected.
4. Enable Wake-on-LAN within the Guest Operating System's network adapter properties.
5. Configure the physical infrastructure (e.g., Cisco switches) to allow directed broadcasts using: ip directed-broadcast ip network-broadcast
6. Ensure UDP ports 7 and 9 are open on all firewalls in the path.

For software downloads, see Download Broadcom Products and Software. If the issue persists, contact Broadcom Support.

Additional Information

• How to create and manage Broadcom Support Cases
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