yum -list 报错

当你通过 ftp  对另一台主机配置  yum 源的时候报错显示如下：

[root@client ~]# yum list               
Loaded plugins: fastestmirror
^C^Ccd ^H^H^Hcd ^H^H^CCould not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=stock error was
14: curl#6 - "Could not resolve host: mirrorlist.centos.org; Unknown error"


 One of the configured repositories failed (Unknown),
 and yum doesn't have enough cached data to continue. At this point the only
 safe thing yum can do is fail. There are a few ways to work "fix" this:

     1. Contact the upstream for the repository and get them to fix the problem.

     2. Reconfigure the baseurl/etc. for the repository, to point to a working
        upstream. This is most often useful if you are using a newer
        distribution release than is supported by the repository (and the
        packages for the previous distribution release still work).

     3. Disable the repository, so yum won't use it by default. Yum will then
        just ignore the repository until you permanently enable it again or use
        --enablerepo for temporary usage:

            yum-config-manager --disable 

     4. Configure the failing repository to be skipped, if it is unavailable.
        Note that yum will try to contact the repo. when it runs most commands,
        so will have to try and fail each time (and thus. yum will be be much
        slower). If it is a very temporary problem though, this is often a nice
        compromise:

            yum-config-manager --save --setopt=.skip_if_unavailable=true

Cannot find a valid baseurl for repo: base/7/x86_64

那么首先检查防火墙是或否关闭 如果没有关闭就使用如下命令进行关闭

systemctl stop firewalld.service

其次检查  SELINUX=disabled 是非为 Disabled或者Permissive状态，如果不是请进行如下操作：

关闭selinux

# vi /etc/sysconfig/selinux

SELINUX=disabled

# getenforce

Disabled

如果还是不是就需要进去 /etc/yum.repos.d/ 目录查看文件

红框内的是需要联网操作的如果你的虚拟机是单网卡而且没有配置外网网卡的话，建议把这几个文件移动到其他目录