index na frente da saída “ip link” ou “ip addr”

Question

Existe um índice na frente de cada interface de rede em ip link show ou ip addr show output. Por exemplo, de 1 a 6 aqui:

root@T42:~# ip link show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:16:41:54:01:93 brd ff:ff:ff:ff:ff:ff
3: bond0: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop state DOWN 
    link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
4: irda0: <NOARP> mtu 2048 qdisc noop state DOWN qlen 8
    link/irda 00:00:00:00 brd ff:ff:ff:ff
5: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:13:ce:8b:99:3e brd ff:ff:ff:ff:ff:ff
6: tun0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 100
    link/none 
root@T42:~# 

Agora, se eu excluir uma interface ( ip link del dev tun0 ) e criar uma interface ( ip tuntap add mode tun ), um novo índice será usado:

root@T42:~# ip link show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:16:41:54:01:93 brd ff:ff:ff:ff:ff:ff
3: bond0: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop state DOWN 
    link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
4: irda0: <NOARP> mtu 2048 qdisc noop state DOWN qlen 8
    link/irda 00:00:00:00 brd ff:ff:ff:ff
5: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:13:ce:8b:99:3e brd ff:ff:ff:ff:ff:ff
7: tun0: <POINTOPOINT,MULTICAST,NOARP> mtu 1500 qdisc noop state DOWN qlen 500
    link/none 
root@T42:~# 

Qual é o propósito desses números de índice? Existe uma maneira de classificar com base nesses números de índice? Por exemplo, se eu criar uma quantidade enorme de interfaces (por exemplo, for i in {2..5000}; do brctl addbr br"$i"; done ), essas interfaces não serão classificadas por número de índice:

root@VM-host:~# ip link show | tail
1279: br1246: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT 
    link/ether 02:de:92:e5:da:b8 brd ff:ff:ff:ff:ff:ff
1023: br990: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT 
    link/ether c2:35:8b:3a:dd:fa brd ff:ff:ff:ff:ff:ff
767: br734: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT 
    link/ether da:e9:52:8f:24:dd brd ff:ff:ff:ff:ff:ff
511: br478: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT 
    link/ether 56:6d:81:a0:71:36 brd ff:ff:ff:ff:ff:ff
255: br222: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT 
    link/ether a6:92:89:f1:ee:4f brd ff:ff:ff:ff:ff:ff
root@VM-host:~# 

    

Answer 1

Os números são meramente por conveniência e são calculados dinamicamente.

These numbers are dynamically calculated, so should not be used to refer to the interfaces.

Mais informações você pode encontrar tools-ip-link e tools-ip-addr .