[root@localhost ~]# yum install lrzsz

Loaded plugins: fastestmirror

Could 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"

[root@localhost ~]# vi  /etc/yum/pluginconf.d/fastestmirror.conf

[main]

enabled=1//把1改為0 

verbose=0

always_print_best_host = true

socket_timeout=3

#  Relative paths are relative to the cachedir (and so works for users as well

# as root).

hostfilepath=timedhosts.txt

maxhostfileage=10

maxthreads=15

#exclude=.gov, facebook

#include_only=.nl,.de,.uk,.ie

[root@localhost ~]# vi /etc/yum.conf

[main]

cachedir=/var/cache/yum/$basearch/$releasever

keepcache=0

debuglevel=2

logfile=/var/log/yum.log

exactarch=1

obsoletes=1

gpgcheck=1

plugins=1//將plugins的值修改為0

installonly_limit=5

bugtracker_url=http://bugs.centos.org/set_project.php?project_id=23&ref=http://bugs.centos.org/bug_report_page.php?category=yum

distroverpkg=centos-release

#  This is the default, if you make this bigger yum won't see if the metadata

# is newer on the remote and so you'll "gain" the bandwidth of not having to

# download the new metadata and "pay" for it by yum not having correct

# information.

#  It is esp. important, to have correct metadata, for distributions like

# Fedora which don't keep old packages around. If you don't like this checking

# interupting your command line usage, it's much better to have something

# manually check the metadata once an hour (yum-updatesd will do this).

# metadata_expire=90m

# PUT YOUR REPOS HERE OR IN separate files named file.repo

# in /etc/yum.repos.d

[root@localhost ~]# yum install lrzsz

Could 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:

[root@localhost ~]# vi /etc/resolv.conf

nameserver 8.8.8.8

nameserver 8.8.4.4

search localdomain