udp-tunnel-outside.service

[Unit]
Description=reverse UDP tunnel (outside agent)
Wants=network-online.target
After=network-online.target

[Service]
Type=simple
Restart=always
RestartSec=60

# adjust the ExecStart line to match your needs
# -l is the UDP port where the outside agent should listen
# for example:
# ExecStart=udp-tunnel -l 51820
ExecStart=udp-tunnel -l {{LISTEN}}

[Install]
WantedBy=multi-user.target