I have my Turris Omnia running in client mode and it’s receiving an IPv4 address from the primary router’s DHCP server. My other clients on the network each receive both an IPv4 and IPv6 address, but the Turris is only receiving the IPv4 one. What configuration changes do I need to make so it receives both addresses?
As from that thread it is clear that DHCP requires 2 interfaces, either on the WAN or LAN, whilst static works with just one iface.
As for the WAN (client) see
On the LAN (client) I stopped bothering with DHCP due the 2 ifaces. For the network manager netifd the naming of wan and wan6 ifaces has a particular meaning/definition but there is no lan6 equivalent.
Why OpenWRT has complicated matters to this extent is not really visible and one could only hope that it will change/improve with their upcoming 19.x branch which then will trickle down into TOS4.x at some point in time.