default preferred-lifetime
Using configuration without any lifetime specifications "config-get" returns the following values:
global scope:
"preferred-lifetime": 3600,
subnet scope:
"max-preferred-lifetime": 3600,
"max-valid-lifetime": 7200,
"min-preferred-lifetime": 3600,
"min-valid-lifetime": 7200,
"preferred-lifetime": 3600,
"valid-lifetime": 7200
Preliminary tests on Kea 2.3.7 appear to show that a "preferred-lifetime" of 3600 seconds is also advertized by Kea.
The ARM makes no mention of a default value for "preferred-lifetime" and may need to be updated
Thomas: In ISC DHCP, if you do not specify preferred lifetime, (and the client doesn't supply hint values),
it sends .625 of the valid lifetime. We could consider changing preferred default to "unspecified"
and doing the same.
By setting a global default of 3600 in Kea, there is no way for a user to have an "unspecified"
value for preferred lifetime