ISC DHCP release on roam flag
release-on-roam flag; When enabled and the dhcpd server detects that a DHCPv6 client (IAID+DUID) has roamed to a new network, it will release the pre-existing leases on the old network and emit a log statement similiar to the following: "Client: <id> roamed to new network, releasing lease: <address>" The server will carry out all of the same steps that would nor- mally occur when a client explicitly releases a lease. When release-on-roam is disabled (the default) the server makes such leases unavailable until they expire or the server is restarted. Clients that need leases in multiple networks must supply a unique IAID in each IA. This parameter may only be specified at the global level.
Make sense for a moving client which for some reasons does not release its address at the previous location. Can be implemented in Kea if there is an easy and fast way to get leases by IAID+DUID only.
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