我在 eth0 上添加了一个标记的 VLAN：
#ip link add link eth0 name eth0.20 type vlan id 20
这导致：
#ip link
2: eth0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 9c:c7:a6:95:65:1c brd ff:ff:ff:ff:ff:ff
....
12: eth0.20@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP
link/ether 9c:c7:a6:95:65:1c brd ff:ff:ff:ff:ff:ff
#ip -d link show eth0.20
70: eth0.20@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP
link/ether 9c:c7:a6:95:65:1c brd ff:ff:ff:ff:ff:ff
vlan id 20 <REORDER_HDR>
#cat /proc/net/vlan/config
VLAN Dev name | VLAN ID
Name-Type: VLAN_NAME_TYPE_RAW_PLUS_VID_NO_PAD
eth0.234 …