Network connectivity lost after unextending HCX network extensions

Products

• VMware HCX

Issue/Introduction

After attempting to unextend network extensions from on-premises to a VMware Cloud during decommissioning activities, virtual machines lose all connectivity. Networks experience connectivity failures, and communication between sites is disrupted. The issue occurs when unextending networks while the remote HCX site is unavailable or has been removed.

The following symptoms may be observed:

Gateway connectivity remains disabled on NSX segments after network unextension attempts. Virtual machines have no routing path to their default gateway, resulting in complete loss of network connectivity. The issue particularly affects inter-site communication when multiple cloud environments are configured.

Steps to validate:

Navigate to NSX Manager → Networking → Segments and review the affected segments. The "Gateway Connectivity" setting shows as "Disabled" on segments that were previously extended via HCX.

Environment

• VMware HCX
• VMware NSX

Cause

The remote HCX Manager becomes unreachable or is deleted before proper cleanup procedures are completed. When this occurs, the Network Extension appliances cannot properly signal NSX to re-enable gateway connectivity on the affected segments. NSX does not automatically restore gateway connectivity when the remote HCX site is unavailable during forced unextension operations, leaving segments in a disabled state.

Resolution

Manually enable gateway connectivity on each affected NSX segment:

1. Log in to NSX Manager
2. Navigate to Networking → Segments
3. Identify the affected segments (previously extended networks)
4. Click Edit on each affected segment
5. Locate the Gateway Connectivity setting
6. Change the setting from Disabled to Enabled
7. Click Save

Repeat steps 4-7 for each affected segment. Network connectivity is restored immediately after enabling gateway connectivity on the segments.

Important: When decommissioning HCX sites or unextending networks, verify that the remote HCX Manager is reachable before initiating unextension operations. If the remote site is unavailable, gateway connectivity must be manually verified and enabled on NSX segments after unextension.

Note: For the proper procedure to decommission HCX environments, see Uninstalling VMware HCX.

If the error persists after following these steps, contact Broadcom Support for further assistance.