support for DHCPv4 RAI Server Identifier Override Suboption 11 (RFC5107)
Kea silently ignores requests that have a server ID that doesn't match one of the interfaces. This is conformant. It also ignores requests that, along the server ID above, include RAI option 11 with the same alien server ID. This second case should not result in a silent ignore, but in an acknowledgement according to RFC 5107 DHCP Server Identifier Override Suboption.