linux/centos如何查看网卡是100M还是1000M？检查100兆还是千兆（1GBPS）带宽接入，请看下面命令
[root@www.ctohome.com]# mii-tool -V
mii-tool.c 1.9 2000/04/28 00:56:08 (David Hinds)
SIOCGMIIREG on eth0 failed: Input/output error
eth0: negotiated 100baseTx-FD, link ok
[root@www.ctohome.com]# mii-tool -v
SIOCGMIIREG on eth0 failed: Input/output error
eth0: negotiated 100baseTx-FD, link ok
product info: vendor 00:aa:00, model 57 rev 0
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
[root@www.ctohome.com]# ethtool eth0
Settings for eth0:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Advertised auto-negotiation: Yes
Speed: 100Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 1
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: pumbag
Wake-on: g
Current message level: 0x00000001 (1)
Link detected: yes
要测试是否是1000M端口，最保险的说用wget测试一个对方的带宽足够大的下载地址：
wget http://cachefly.cachefly.net/100mb.test
--2011-03-14 22:19:12-- http://cachefly.cachefly.net/100mb.test
Resolving cachefly.cachefly.net... 205.234.175.175
Connecting to cachefly.cachefly.net|205.234.175.175|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 104857600 (100M) [application/octet-stream]
Saving to: `100mb.test.2'
100%[===================================================================================================================>] 104,857,600 39.1M/s in 2.6s
2011-03-14 22:19:14 (39.1 MB/s) - `100mb.test.2' saved [104857600/104857600]
如果下载速度能超过15MB/s，那么不是100M端口了，通常就是1000M端口
如果是独立服务器，可以通过下面命令核查网卡端口：
[root@www.ctohome.com ]# ethtool eth0
Settings for eth0:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Advertised auto-negotiation: Yes
Speed: 1000Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 1
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: pumbag
Wake-on: g
Current message level: 0x00000001 (1)
Link detected: yes