NICのプロパティや状態を確認する・ethtoolコマンド (Linux)

ethtoolコマンドでNICを指定するとNICのプロパティや状態を確認することができます。
CentOS 7 で確認しました。

NICの名前を調べる

ifconfigコマンドでNICの名前を調べる。

[root@host2 ~]# ifconfig
enp14s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.1.2  netmask 255.255.255.0  broadcast 192.168.1.255
        inet6 2001:a453:61e1:9000:7ae7:d1ff:feda:833c  prefixlen 64  scopeid 0x0<global>
        inet6 fe80::7ae7:d1ff:feda:833c  prefixlen 64  scopeid 0x20<link>
        ether 78:e7:d1:da:83:3c  txqueuelen 1000  (Ethernet)
        RX packets 6311  bytes 3475948 (3.3 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 5555  bytes 428393 (418.3 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 17  

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 0  (Local Loopback)
        RX packets 6  bytes 560 (560.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 6  bytes 560 (560.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

ethoolを使ってみる

[root@host2 ~]# ethtool enp14s0                                                 
Settings for enp14s0:
        Supported ports: [ TP ]
        Supported link modes:   10baseT/Half 10baseT/Full 
                                100baseT/Half 100baseT/Full 
                                1000baseT/Half 1000baseT/Full 
        Supported pause frame use: No
        Supports auto-negotiation: Yes
        Advertised link modes:  10baseT/Half 10baseT/Full 
                                100baseT/Half 100baseT/Full 
                                1000baseT/Half 1000baseT/Full 
        Advertised pause frame use: Symmetric
        Advertised auto-negotiation: Yes
        Link partner advertised link modes:  10baseT/Half 10baseT/Full 
                                             100baseT/Half 100baseT/Full 
        Link partner advertised pause frame use: Symmetric
        Link partner advertised auto-negotiation: Yes
        Speed: 100Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 1
        Transceiver: internal
        Auto-negotiation: on
        MDI-X: on
        Supports Wake-on: g
        Wake-on: g
        Current message level: 0x000000ff (255)
                               drv probe link timer ifdown ifup rx_err tx_err
        Link detected: yes