> As another thought do you know what DHCPv6 client/server is being > used. > There was a fairly recent bugfix for busybox that was needed because >the v6 code was using the wrong MAC address.
I'm the customer experiencing this issue. It appears unrelated to the DHCP server software. On the Turris Mox with Debian 10 we have isc-dhcp-server 4.4.1-2. Clients are Xubuntu 20.04 withNetworkManager 1.22.10-1ubuntu2.1 using isc-dclient 4.4.1-2.1ubuntu5. Quoting from another email I sent to Turris: We've now done more testing and CONFIRMED the Mox is losing DHCPv6 solicit packets. Specifically, it seems the 88E6190 hardware switches in the Peridot module is swallowing IPv6 multicast packets (sent to ff02::1:2 ). We tested this by mirroring the Mox LAN port on an external switch and saw the DHCPv6 solicit packet egress the switch but the Mox kernel didn't see it ingress (using tcpdump).