Hello,As mentioned in [0], isc-dhcp-server has failed state in Stretch (via systemd). /etc/init.d/isc-dhcp-server seems to be "buggy" on IPv6 part.
With this settings in /etc/default/isc-dhcp-server : -- INTERFACES="MY_INTERFACE_NAME" INTERFACESv4="MY_INTERFACE_NAME" -- isc-dhcp-server service can be manage with systemd. -- Nicolas [0] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=792894#56
