This article will explain the issue with DHCPv6 ZTP is not functional on QFX5200 switches running the Flex version of the software.

We observed that the device does not send out any DHCPv6 packets. Our upstream devices correctly set the Managed Configuration (M) flag in the NDv6 (Neighbor Discovery for IPv6) announcements. However, under the Flex firmware, we only see BOOTP/DHCP packets for IPv4.

The root cause of DHCPv6 ZTP not working in the Flex version is a difference in the factory default configuration compared to the non-Flex image. Specifically, the default config in the Flex version leaves the IRB interface in a down state, preventing it from receiving an IPv6 address and initiating DHCPv6 communication.

The feature "ZTP over DHCPv6" is supported starting from version 20.2R1-S1, but only on non-Flex images.

Support for ZTP over DHCPv6 using HTTP/HTTPS on Flex images is available starting from version 24.4R1.