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本文包含内容：
CentOS系统在speedtest进行网速测试
Centos 7 Linux系统修改网卡名称为ethx
CentOS 7 小化安装后找不到 ifconfig 命令的解决办法
Centos虚拟机克隆后MAC地址变动导致网络不通问题的解决办法
1，用www.speedtest.cn的测速方案（推荐）
curl -O https://ftp.speedtest.cn/cli/linux/speedtest-cn-cli && chmod +x speedtest-cn-cli
./speedtest-cn-cli
2，用www.speedtest.net的测速方案
执行命令进行自动选择节点进行测速：
wget -O speedtest-cli https://raw.githubusercontent.com/sivel/speedtest-cli/master/speedtest.py
chmod +x speedtest-cli
./speedtest-cli --share
输入命令查看中国的测速节点
./speedtest-cli --list | grep China
输入测速节点编号进行测速
./speedtest-cli --server=4515 --share
1、查看Centos7系统默认的网卡配置（eno16777736）
[root@server ~]# ifconfig eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 #系统默认的网卡名称 inet 172.16.0.2 netmask 255.255.0.0 broadcast 172.16.255.255 inet6 fe80::20c:29ff:fefa:dbfa prefixlen 64 scopeid 0x20<link> ether 00:0c:29:fa:db:fa txqueuelen 1000 (Ethernet) RX packets 6699 bytes 8261881 (7.8 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 3006 bytes 215704 (210.6 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 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 25200 bytes 1468912 (1.4 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 25200 bytes 1468912 (1.4 MiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 [root@server ~]#
2、编辑centos7系统默认的网卡配置文件，将NAME、DEVICE选项修改为eth0
[root@server ~]# vi /etc/sysconfig/network-scripts/ifcfg-eno16777736 TYPE=Ethernet BOOTPROTO=none TYPE=Ethernet BOOTPROTO=none TYPE=Ethernet BOOTPROTO=none DEFROUTE=yes IPV4_FAILURE_FATAL=yes IPV6INIT=yes IPV6_AUTOCONF=yes IPV6_DEFROUTE=yes IPV6_FAILURE_FATAL=noNAME=eno16777736 此处修改为#NAME=eth0UUID=68062773-e078-4f64-8df6-3cbdf4730a4bDEVICE=eno16777736 此处修改为#DEVICE=eth0ONBOOT=yes DNS1=192.168.1.1 DNS2=114.114.114.114 IPADDR=172.16.0.2 PREFIX=16 IPADDR1=172.16.0.4 PREFIX1=16 IPADDR2=172.16.0.5 PREFIX2=16 GATEWAY=172.16.0.1
3、将Centos7系统网卡配置文件ifcfg-eno16777736重命名为ifcfg-eth0
[root@server ~]# mv /etc/sysconfig/network-scripts/ifcfg-eno16777736 /etc/sysconfig/network-scripts/ifcfg-eth0
4、更改/etc/default/grub启动菜单传递给内核的参数，在GRUB_CMDLINE_LINUX变量中加入“net.ifnames=0 biosdevname=0”
[root@server ~]# ls -ld /etc/sysconfig/grub lrwxrwxrwx. 1 root root 17 Aug 26 2017 /etc/sysconfig/grub -> /etc/default/grub [root@server ~]# vi /etc/default/grub GRUB_TIMEOUT=5 GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)" GRUB_DEFAULT=saved GRUB_DISABLE_SUBMENU=true GRUB_TERMINAL_OUTPUT="console" GRUB_CMDLINE_LINUX="crashkernel=auto net.ifnames=0 biosdevname=0 rhgb quiet" #添加GRUB_CMDLINE_LINUX变量net.ifnames=0 biosdevname=0GRUB_DISABLE_RECOVERY="true"
5、运行grub2-mkconfig -o /boot/grub2/grub.cfg命令重新生成grub菜单并更新内核参数
[root@server ~]# grub2-mkconfig -o /boot/grub2/grub.cfg Generating grub configuration file ... Found linux image: /boot/vmlinuz-3.10.0-327.el7.x86_64 Found initrd image: /boot/initramfs-3.10.0-327.el7.x86_64.img Found linux image: /boot/vmlinuz-0-rescue-f818c03720a04698929d06982f96d567 Found initrd image: /boot/initramfs-0-rescue-f818c03720a04698929d06982f96d567.img done
6、修改/etc/udev/rules.d/90-eno-fix.rules配置文件，将NAME=" eno16777736"修改为NAME="eth0"
[root@server ~]# cat /etc/udev/rules.d/90-eno-fix.rules # This file was automatically generated on systemd update
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:0c:29:fa:db:fa", NAME=" eno16777736"
[root@server ~]# sed -i 's#NAME="eno16777736"#NAME="eth0"#g' /etc/udev/rules.d/90-eno-fix.rules
[root@server ~]# cat /etc/udev/rules.d/90-eno-fix.rules
# This file was automatically generated on systemd updateSUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:0c:29:fa:db:fa", NAME="eth0" #修改NAME变量为eth07、重启Centos7系统，完成网卡改名
[root@server ~]# reboot
8、验证Centos7系统网卡改名的结果
[root@server ~]# ifconfigeth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 #查看系统网卡名称已经设置为eth0 inet 172.16.0.2 netmask 255.255.0.0 broadcast 172.16.255.255 inet6 fe80::20c:29ff:fefa:dbfa prefixlen 64 scopeid 0x20<link> ether 00:0c:29:fa:db:fa txqueuelen 1000 (Ethernet) RX packets 339 bytes 28141 (27.4 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 190 bytes 25047 (24.4 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 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 8034 bytes 469008 (458.0 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 8034 bytes 469008 (458.0 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 [root@server ~]#
就像我们所知道的，“ifconfig”命令用于配置GNU/Linux系统的网络接口。它显示网络接口卡的详细信息，包括IP地址，MAC地址，以及网络接口卡状态之类。但是，该命令已经过时了，而且在最小化版本的RHEL 7以及它的克隆版本CentOS 7，Oracle Linux 7和Scientific Linux 7中也找不到该命令。
CentOS 7最小化系统，使用“ip addr”和“ip link”命令来查找网卡详情。要知道统计数据，可以使用“ip -s link”。
要查看网卡细节，输入以下命令：
ip addr
输出样例：
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 inet 127.0.0.1/8 scope host lo inet6 ::1/128 scope host valid_lft forever preferred_lft forever2: venet0: <BROADCAST,POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN link/void inet 127.0.0.1/32 scope host venet0 inet 192.168.1.101/32 brd 192.168.1.101 scope global venet0:0
要查看网络接口统计数据，输入命令：
ip link
输出样例：
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN mode DEFAULT link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:002: venet0: <BROADCAST,POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT link/void
或者
ip -s link
输出样例：
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN mode DEFAULT link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 RX: bytes packets errors dropped overrun mcast 0 0 0 0 0 0 TX: bytes packets errors dropped carrier collsns 0 0 0 0 0 0 2: venet0: <BROADCAST,POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT link/void RX: bytes packets errors dropped overrun mcast 8515667 6667 0 0 0 0 TX: bytes packets errors dropped carrier collsns 300403 4249 0 0 0 0
如果你不知道在哪里可以找到ifconfig命令，请按照以下简单的步骤来找到它。首先，让我们找出哪个包提供了ifconfig命令。要完成这项任务，输入以下命令：
yum provides ifconfig
输出样例：
Loaded plugins: fastestmirrorLoading mirror speeds from cached hostfile * base: centos.aol.in * extras: centos.aol.in * updates: centos.aol.innet-tools-2.0-0.17.20131004git.el7.x86_64 : Basic networking toolsRepo : @baseMatched from:Filename : /usr/sbin/ifconfig
或者你也可以使用以下命令。
yum whatprovides ifconfig
这里，“provides”或者“whatprovides”开关用于找出某个包提供了某些功能或文件。
就像你在上面的输出中所看到的，net-tools包提供了ifconfig命令。因此，让我们安装net-tools包来使用ifconfig命令。
yum install net-tools
现在，你就可以像以往一样使用ifconfig命令了。
ifconfig -a
输出样例：
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 16436 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 0 (Local Loopback) RX packets 0 bytes 0 (0.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 0 bytes 0 (0.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 venet0: flags=211<UP,BROADCAST,POINTOPOINT,RUNNING,NOARP> mtu 1500 inet 127.0.0.1 netmask 255.255.255.255 broadcast 0.0.0.0 destination 127.0.0.1 unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 0 (UNSPEC) RX packets 7073 bytes 8549159 (8.1 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 4611 bytes 359201 (350.7 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 venet0:0: flags=211<UP,BROADCAST,POINTOPOINT,RUNNING,NOARP> mtu 1500 inet 192.168.1.101 netmask 255.255.255.255 broadcast 192.168.1.101 destination 192.168.1.101 unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 0 (UNSPEC)
尽情享受吧！
CentOS Device does not seem to be present
故障现象：
# service network restart
Shutting down loopback insterface: [ OK ]
Bringing up loopback insterface: [ OK ]
Bringing up interface eth0: Device eth0 does not seem to be present,delaying initialization. [FAILED]
解决办法:
1.修改Centos虚拟机克隆机的HWADDR为ifconfig -a的MAC地址
# ifconfig -a
eth0 Link encap:Ethernet HWaddr 00:0C:29:DC:79:AF
…………………………
…………………………
看到上面的“HWaddr 00:0C:29:DC:79:AF”没有？把“00:0C:29:DC:79:AF”记录下来，然后
# vim /etc/sysconfig/network-scripts/ifcfg-eth0
把里面的HWADDR改成刚才记下来的那个，
即：HWADDR=00:0C:29:DC:79:AF
保存退出。
2.接着进行如下操作
# rm -rf /etc/udev/rules.d/70-persistent-net.rules
# reboot
…………………………
# service network restart
Shutting down loopback insterface: [ OK ]
Bringing up loopback insterface: [ OK ]
Bringing up interface eth0: [ OK ]
看到三个OK，网络配置成功
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