查看Linux下网卡状态或 是否连接

分类：

1) 通过mii-tool指令
[root@localhost root]# mii-tool
eth0: negotiated 100baseTx-FD, link ok
eth1: no link
或
[root@localhost root]# mii-tool -v
eth0: negotiated 100baseTx-FD, link ok
product info: vendor 00:50:43, model 2 rev 3
basic mode: autonegotiation enabled
basic status: autonegotiation complete, link ok
capabilities: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD
advertising: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD flow-control
link partner: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD
eth1: no link
product info: vendor 00:50:43, model 2 rev 3
basic mode: autonegotiation enabled
basic status: no link
capabilities: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD
advertising: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD flow-control
或
[root@localhost root]# mii-tool -w
21:20:33 eth0: negotiated 100baseTx-FD, link ok
21:20:33 eth1: no link
//mii-tool主要是用于配置网卡工作模式的指令，同时也可以进行查询、监控等工作！

2)
[root@localhost /]# /etc/init.d/network status
Configured devices:
lo eth0 eth1
Currently active devices:
lo eth0
等同于
[root@localhost root]# service --status-all
............
............
Configured devices:
lo eth0 eth1
Currently active devices:
lo eth0
............
............
3)ifconfig -a
[root@localhost /]# ifconfig -a
eth0 Link encap:Ethernet HWaddr 00:09:6B:09:08:FC
inet addr:192.168.10.1 Bcast:192.168.10.255 Mask:255.255.255.0
inet6 addr: fe80::209:6bff:fe09:8fc/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:106732953 errors:0 dropped:0 overruns:0 frame:0
TX packets:104379788 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:2351331877 (2.1 GiB) TX bytes:391707945 (373.5 MiB)
Base address:0x2500 Memory:fbfe0000-fc000000
eth1 Link encap:Ethernet HWaddr 00:09:6B:09:08:FD
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
Base address:0x2540 Memory:fbfc0000-fbfe0000

4)ethtool

#ethtool eth0
Settings for eth0:
Supported ports: [ MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Advertised auto-negotiation: Yes
Speed: 100Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 1
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: g
Wake-on: d
Current message level: 0x000000ff (255)
Link detected: yes

#ethtool eth1

Settings for eth1:
Supported ports: [ MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Advertised auto-negotiation: Yes
Speed: Unknown! (0)
Duplex: Half
Port: Twisted Pair
PHYAD: 1
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: g
Wake-on: d
Current message level: 0x000000ff (255)
Link detected: no
从上面可以看出eth0 处于连接状态，eth1没有连接