This bug was fixed in the package isc-dhcp - 4.2.4-7ubuntu12.9
--------------- isc-dhcp (4.2.4-7ubuntu12.9) trusty; urgency=medium
* [4b8251a] DHCPv6: fix socket handling so multiple DHCPv6 local clients will successfully get addresses (LP: #1689854)
-- Dan Streetman <email address hidden> Wed, 10 May 2017 12:19:35 -0300
This bug was fixed in the package isc-dhcp - 4.2.4-7ubuntu12.9
---------------
isc-dhcp (4.2.4-7ubuntu12.9) trusty; urgency=medium
* [4b8251a] DHCPv6: fix socket handling so multiple DHCPv6 local clients will
successfully get addresses (LP: #1689854)
-- Dan Streetman <email address hidden> Wed, 10 May 2017 12:19:35 -0300