[Unit]
Description=ISC DHCP IPv6 server
Documentation=man:dhcpd(8)
Wants=network-online.target
After=network-online.target
After=time-sync.target
ConditionPathExists=/etc/default/isc-dhcp-server
ConditionPathExists=|/etc/ltsp/dhcpd6.conf
ConditionPathExists=|/etc/dhcp/dhcpd6.conf

[Service]
EnvironmentFile=/etc/default/isc-dhcp-server
RuntimeDirectory=dhcp-server
# The leases files need to be root:dhcpd even when dropping privileges
ExecStart=/bin/sh -ec '\
    CONFIG_FILE=/etc/dhcp/dhcpd6.conf; \
    if [ -f /etc/ltsp/dhcpd6.conf ]; then CONFIG_FILE=/etc/ltsp/dhcpd6.conf; fi; \
    [ -e /var/lib/dhcp/dhcpd6.leases ] || touch /var/lib/dhcp/dhcpd6.leases; \
    chown root:dhcpd /var/lib/dhcp /var/lib/dhcp/dhcpd6.leases; \
    chmod 775 /var/lib/dhcp ; chmod 664 /var/lib/dhcp/dhcpd6.leases; \
    exec dhcpd -user dhcpd -group dhcpd -f -6 -pf /run/dhcp-server/dhcpd6.pid -cf $CONFIG_FILE $INTERFACESv6'

[Install]
WantedBy=multi-user.target