如何解决 Linux (Centos 6.7) 上的 CentOS-Base.repo 的 baseurl 问题以运行“yum install ftp”

Question

我正在安装 FTP 并发现这个问题，导致我无法安装 yum。参考了很多地方，yum clean all并配置了 CentOs-Base.repo，将Vault.centos.org 作为-Base 的baseurl。我仍然无法使用 yum 安装 ftp。我收到以下错误：

[root@ts-htn-01 yum.repos.d]# yum update
Loaded plugins: fastestmirror, security
Setting up Update Process
Repository base is listed more than once in the configuration
Repository updates is listed more than once in the configuration
Repository extras is listed more than once in the configuration
Repository centosplus is listed more than once in the configuration
Repository contrib is listed more than once in the configuration
Repository '-dc' is missing name in configuration, using id
Loading mirror speeds from cached hostfile
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=6&arch=x86_64&repo=os&infra=stock error was
14: PYCURL ERROR 7 - "couldn't connect to host"
https://vault.centos.org/6.7/os/x86_64/repodata/repomd.xml: [Errno 14] PYCURL ERROR 7 - "couldn't connect to host"
Trying other mirror.
Error: Cannot retrieve repository metadata (repomd.xml) for repository: base. Please verify its path and try again
[root@ts-htn-01 yum.repos.d]#

我的 http 服务正在运行：

[root@ts-htn-01 yum.repos.d]# service httpd status
httpd (pid  6650) is running...
[root@ts-htn-01 yum.repos.d]#

我对Vault.centos.org和mirrorlist.centos.org的ping工作正常。我应该将其添加到主机连接中吗？如果是，请告诉我如何做。请帮忙。提前致谢。