[Unit]
Description=macchanger on %I
Wants=network-pre.target
Before=network-pre.target
BindsTo=sys-subsystem-net-devices-%i.device
After=sys-subsystem-net-devices-%i.device

[Service]
RemainAfterExit=yes
ExecStart=/usr/bin/macchanger -r %I
Type=oneshot

[Install]
WantedBy=multi-user.target