Corrected ExecStop for nspawn NAT service.

files/nspawn-nat.service

@@ -9,7 +9,7 @@ Type=oneshot
 RemainAfterExit=yes
 Environment=network="192.168.123.0/24"
 ExecStart=/sbin/iptables -w -t nat -A POSTROUTING -s "$network" ! -d "$network" -j MASQUERADE
-ExecStop=/sbin/iptables -w -t nat -D POSTROUTING -s 192.168.123.0/24 ! -d 192.168.123.0/24 -j MASQUERADE
+ExecStop=/sbin/iptables -w -t nat -D POSTROUTING -s "$network" ! -d "$network" -j MASQUERADE
 
 [Install]
 WantedBy=network.target