The IPv4 and IPv6 DHCP relay service implementation supports specifying a listen port to listen for DHCP packets which should be relayed.
At the time of this writing only the Linux DHCP client supports requesting an address over a non standard port (UDP 67). Supporting DHCP ports is only useful for debugging but I still don't get the real use-case here.
Proposal:
Remove DHCP relay port options in IPv4 and IPv6 implementation, which requires a proper migration script, to