vCenter UI displays incorrect IPv6 default gateway for VMkernel interfaces using Router Advertisement (RA) on shared TCP/IP stack
search cancel

vCenter UI displays incorrect IPv6 default gateway for VMkernel interfaces using Router Advertisement (RA) on shared TCP/IP stack

book

Article ID: 434520

calendar_today

Updated On:

Products

VMware vCenter Server VMware vSphere ESXi

Issue/Introduction

  • In vCenter, the UI may display an incorrect IPv6 default gateway for VMkernel (VMK) interfaces when multiple VMKs share the same TCP/IP stack but use different gateway configuration methods.
  • The vCenter UI shows the same IPv6 default gateway for multiple VMkernel interfaces, even when they are on different VLANs or L2 segments.
  • A VMkernel interface configured with IPv6 Router Advertisement (RA) or DHCPv6 shows a gateway that does not match the actual gateway used by the host.
  • The gateway displayed in the vCenter UI differs from the output of ESXi CLI commands such as: esxcli network ip interface ipv6 get esxcli network ip route ipv6 list Traffic forwarding works correctly despite the incorrect UI display.

Environment

  • vCenter 8.x
  • vCenter 9.x
  • ESXi 8.x
  • ESX 9.x

Cause

This is a known limitation of the vCenter UI data model and API. The vCenter UI determines the default gateway primarily from: TCP/IP stack-level configuration (netStackInstance.ipRouteConfig), or VMK-level override (ipRouteSpec) when present for VMkernel interfaces using RA or DHCPv6.The interface-specific IPv6 gateway learned via RA is not populated in ipRouteSpec. As a result: The UI falls back to the TCP/IP stack default gateway .This causes incorrect display when multiple VMKs on the same stack have different effective gateways. From a datapath perspective: The ESXi host uses the correct interface-specific gateway learned via RA the incorrect value is only in the UI display

Resolution

There is currently no workaround or fix. This behavior is expected and has been classified as a limitation requiring new API support.

Recommended actions: Use ESXi CLI commands to verify the actual IPv6 gateway:

esxcli network ip interface ipv6 get

esxcli network ip route ipv6 list

Do not rely solely on vCenter UI for IPv6 gateway validation in RA/DHCPv6 scenarios

Additional Information

This issue does not impact actual traffic forwarding The ESXi routing table and datapath behavior are correct The issue is limited to how the vCenter UI aggregates and displays gateway information

Powered by Wolken Software