Не стартует автоматически при загрузке операционки демон knockd

Debian GNU/Linux 9.8 (stretch)

Linux gw 4.9.0-8-686-pae #1 SMP Debian 4.9.144-3.1 (2019-02-19) i686 GNU/Linux

Содержимое конфигов:

/etc/default/knockd

# control if we start knockd at init or not
# 1 = start
# anything else = don't start
# PLEASE EDIT /etc/knockd.conf BEFORE ENABLING
START_KNOCKD=1

# command line options
#KNOCKD_OPTS="-i eth1"
KNOCKD_OPTS="-v -i ext"

/etc/knockd.conf

[options]
        UseSyslog

[RDP01]
    Sequence    = 27000:udp,27001:udp,27002:udp
    Seq_Timeout = 7
    Command     = /sbin/ipset add knock_hosts_set %IP%

/lib/systemd/system/knockd.service

[Unit]
Description=Port-Knock Daemon
After=network.target
Documentation=man:knockd(1)

[Service]
EnvironmentFile=-/etc/default/knockd
ExecStart=/usr/sbin/knockd $KNOCKD_OPTS
ExecReload=/bin/kill -HUP $MAINPID
KillMode=mixed
SuccessExitStatus=0 2 15
ProtectSystem=full
CapabilityBoundingSet=CAP_NET_RAW CAP_NET_ADMIN

Restart=always
OOMScoreAdjust=-100

Состояние сервиса сразу после загрузки операционки:

systemctl status knockd