Content-Transfer-Encoding: binary Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 To: dhcp-public@isc.org From: cathya@isc.org Content-Disposition: inline X-Mailer: MIME-tools 5.508 (Entity 5.508) Date: Thu, 12 Jul 2018 15:04:41 +0000 Subject: Extend 'ignore-client-uids' to include load-balancing lease allocation decisions Message-ID: X-RT-Interface: Web X-RT-Original-Encoding: utf-8 Content-Length: 1101 The ignore-client-uids option is supposed to make it easier to handle PXE-boot clients that would like the same IP address to be allocated to them during both boot phases, the first boot not providing a client uid (therefore being assigned a lease based solely on MAC address) and the second sending a client uid, and therefore being 'seen' as a new client. At present this mostly works, but there is (at least) one corner case: in a load-balancing situation, and where the lease initially granted has expired, the client DISCOVER might be load-balanced to the other failover peer because of 'on the fly' load balancing based on hashing the client identifier (mac or uid as appropriate), and thus still be given a different address. This can introduce some instability into the dual-boot IP address assignments. It would be better if, when 'ignore-client-uids' has been specified, that the hashing for load-balancing purposes also ignores client uids. (There may also be other locations in DHCP logic that could also benefit from this setting being observed but which haven't yet been identified).