не может использовать yum, так как удаление постфикса

yum remove postfix сделал так, что yum больше не работает, как и репозиторий wget epel ... ничего не найдено.

В таком случае лучше переустановить Centos?

Could not retrieve mirrorlist http://mirrorlist.centos.org/? release=7&arch= error was
14: curl#6 - "Could not resolve host: mirrorlist.centos.org; Unknown error"
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch= error was
14: curl#6 - "Could not resolve host: mirrorlist.centos.org; Unknown error"
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch= error was
14: curl#6 - "Could not resolve host: mirrorlist.centos.org; Unknown error"
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch= error was
14: curl#6 - "Could not resolve host: mirrorlist.centos.org; Unknown error"
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch= error was
14: curl#6 - "Could not resolve host: mirrorlist.centos.org; Unknown error"
repo id                         repo name                             status
addons/7                        CentOS-7 - Addons                     enabled: 0
base/7                          CentOS-7 - Base                       enabled: 0
centosplus/7                    CentOS-7 - Plus                       enabled: 0
contrib/7                       CentOS-7 - Contrib                    disabled
extras/7                        CentOS-7 - Extras                     enabled: 0
updates/7                       CentOS-7 - Updates                    enabled: 0
repolist: 0


ID | Login user               | Date and time    | Action(s)      | Altered
-------------------------------------------------------------------------------
85 | root <root>              | 2015-11-29 15:20 | Erase          |    2 EE
84 | root <root>              | 2015-11-29 15:20 | Erase          |    1   
83 | root <root>              | 2015-11-29 15:20 | Erase          |    1 EE
82 | root <root>              | 2015-11-29 11:28 | Erase          |    1   
81 | root <root>              | 2015-11-29 11:22 | Install        |    2   
80 | root <root>              | 2015-11-25 11:16 | Install        |    1   
79 | root <root>              | 2015-11-25 11:16 | Erase          |    1   
78 | root <root>              | 2015-11-25 10:32 | Install        |    1   
77 | root <root>              | 2015-11-25 10:09 | Install        |    1   
76 | root <root>              | 2015-11-25 09:48 | Install        |    2   
75 | root <root>              | 2015-11-25 09:45 | I, U           |   47 EE
74 | root <root>              | 2015-11-24 18:58 | Erase          |    1   
73 | root <root>              | 2015-11-24 18:58 | Erase          |    1   
72 | root <root>              | 2015-11-24 17:18 | Install        |    1   
71 | root <root>              | 2015-11-24 17:16 | Install        |    1   
70 |  <me>                    | 2015-11-18 21:32 | Install        |    1   
69 | root <root>              | 2015-11-18 21:27 | Erase          |    1 EE
68 | root <root>              | 2015-11-18 19:50 | I, U           |    3   
67 | root <root>              | 2015-08-07 17:45 | Reinstall      |    1   
66 | root <root>              | 2015-08-03 19:57 | Install        |  127