Photon OS 5.0 fails to acquire IPv6 address by default

Products

• VMware vSphere ESX 8.x

Issue/Introduction

In a Photon OS 5.0 environment, the system fails to automatically acquire an IPv6 address after startup.

Environment

VMware vSphere ESXi 8.x
VMware vSphere ESX 9.x
Photon OS 5.0

Cause

The default network configuration disables the receipt of IPv6 Router Advertisements (RA). Specifically, the IPv6AcceptRA parameter is set to no in the systemd-networkd configuration, and the kernel parameter net.ipv6.conf.eth0.accept_ra defaults to 0.

Resolution

Use one of the following two methods to resolve this issue and restore IPv6 address acquisition capabilities.

Method 1: Modify systemd-networkd configuration (Persistent)

1. Edit the network configuration file /etc/systemd/network/99-dhcp-en.network.

2. Locate the [Network] section and modify the IPv6AcceptRA value from no to yes:
   
   IPv6AcceptRA=yes
   
   

3. Restart the network service to apply the changes:
   
   systemctl restart systemd-networkd

 

Method 2: Modify kernel parameter via sysctl (Runtime)

1. Execute the following command to set the accept_ra parameter to 1 for the target network interface (e.g., eth0):
   
   sysctl -w net.ipv6.conf.eth0.accept_ra=1
   
   

2. To persist this setting across reboots, add net.ipv6.conf.eth0.accept_ra=1 to the /etc/sysctl.d/99-sysctl.conf file and execute sysctl -p to reload the configuration.