linux无法联网使用yum提示cannot find a valid baseurl for repobase7x86_64

每次安装新镜像时会遇到物理机有网络新安装的linux中却无法与物理机通信(不能连网)，只能玩一些预装功能、命令，无法使用各种常用工具(特别是MINI版连ifconfig都没有o(╥﹏╥)o)，下面记录解决过程【提示cannot find a valid baseurl for repobase7x86_64也是因为没有网络】。

1、首先使用ip addr查看网卡名称

[root@ ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:22:80:e3 brd ff:ff:ff:ff:ff:ff

从上面的信息中可以看到我的网卡名称叫ens33(不同版本的系统名称存在差异)

2、修改配置文件，将配置文件中的ONBOOT=no改为ONBOOT=yes并保存

[root@ ~]# cat -n /etc/sysconfig/network-scripts/ifcfg-ens33
     1  TYPE=Ethernet
     2  PROXY_METHOD=none
     3  BROWSER_ONLY=no
     4  BOOTPROTO=dhcp
     5  DEFROUTE=yes
     6  IPV4_FAILURE_FATAL=no
     7  IPV6INIT=yes
     8  IPV6_AUTOCONF=yes
     9  IPV6_DEFROUTE=yes
    10  IPV6_FAILURE_FATAL=no
    11  IPV6_ADDR_GEN_MODE=stable-privacy
    12  NAME=ens33
    13  UUID=023bce24-ebd3-4d19-9911-e8b662axxxxx
    14  DEVICE=ens33
    15  ONBOOT=no

3、reboot重启

4、再次查看ip

[root@ ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:22:80:e4 brd ff:ff:ff:ff:ff:ff
    inet 192.168.142.141/24 brd 192.168.142.255 scope global noprefixroute dynamic ens33
       valid_lft 1653sec preferred_lft 1653sec
    inet6 fe80::a0b:b3fa:fcdb:a92e/64 scope link noprefixroute
       valid_lft forever preferred_lft forever

可以看到重启后正常联网了也能看到局域网所属ip了192.168.142.141。

使用yum安装ifconfig试试能不能成功联网安装：

[root@ ~]# yum search ifconfig  # 查找ifconfig所属包
已加载插件：fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirrors.shu.edu.cn
 * extras: mirrors.zju.edu.cn
 * updates: ftp.sjtu.edu.cn
========================================================================== 匹配：ifconfig ==========================================================================
net-tools.x86_64 : Basic networking tools
[root@ ~]# yum install net-tools.x86_64  # 安装对应工具包
已加载插件：fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirrors.shu.edu.cn
 * extras: mirrors.zju.edu.cn
 * updates: mirrors.nju.edu.cn
正在解决依赖关系
--> 正在检查事务
---> 软件包 net-tools.x86_64.0.2.0-0.24.20131004git.el7 将被 安装
--> 解决依赖关系完成

依赖关系解决

====================================================================================================================================================================
 Package                              架构                              版本                                                  源                               大小
====================================================================================================================================================================
正在安装:
 net-tools                            x86_64                            2.0-0.24.20131004git.el7                              base                            306 k

事务概要
====================================================================================================================================================================
安装  1 软件包

总下载量：306 k
安装大小：918 k
Is this ok [y/d/N]: y
Downloading packages:
net-tools-2.0-0.24.20131004git.el7.x86_64.rpm                                                                                                | 306 kB  00:00:00
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  正在安装    : net-tools-2.0-0.24.20131004git.el7.x86_64                                                                                                       1/1
  验证中      : net-tools-2.0-0.24.20131004git.el7.x86_64                                                                                                       1/1 

已安装:
  net-tools.x86_64 0:2.0-0.24.20131004git.el7                                                                                                                       

完毕！

# 测试ifconfig是否可用
[root@ ~]# ifconfig
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.142.141  netmask 255.255.255.0  broadcast 192.168.142.255
        inet6 fe80::a0b:b3fa:fcdb:a93e  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:22:80:e3  txqueuelen 1000  (Ethernet)
        RX packets 8046  bytes 10053684 (9.5 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 2085  bytes 202580 (197.8 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 1000  (Local Loopback)
        RX packets 4  bytes 352 (352.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 4  bytes 352 (352.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

成功安装，到此就成功解决不能联网的问题了^_^