ESXi host is inaccessible via its IPv6 address

Products

• VMware vSphere ESXi

Issue/Introduction

This article addresses potential conflicts when manually configuring a static address on an IPV6 ESXi host while Router Advertisement (RA) messages are active.

When a static address is manually set on the ESXi host, two primary issues may arise if RA messages are concurrently advertising the same or similar addresses:

Environment

 

VMware vSphere ESXi

 

Cause

If the RA message advertises the exact static address or a similar address within the same subnet, the static address could be flagged as a duplicate. This may lead to the device being unable to use the static address.

 

In cases where the static address falls within a subnet range that the RA advertises, there may be conflicting subnet parameters. For example, the RA might assign a different default gateway or network prefix than what was set manually, leading to routing inconsistencies.

 

Resolution

To prevent these conflicts, ensure that Router Advertisements are disabled when using static addresses. This can be achieved by turning off RA on the relevant interface using the following command esxcli network ip interface ipv6 set -i <vmk> -r off This ensures that only the manual settings are applied, eliminating issues due to duplicate addresses and subnet mismatches.