今天在linux环境通过yum安装软件报了以下错误：
[root@multi-mysql yum.repos.d]# yum install ncurses devel -y
Loaded plugins: fastestmirror, security
Loading mirror speeds from cached hostfile
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=6&arch=x86_64&repo=os error was
14: PYCURL ERROR 6 - "Couldn't resolve host 'mirrorlist.centos.org'"
Error: Cannot find a valid baseurl for repo: base
从字面意义上看是不能解析mirrorlist.centos.org这个地址，应该是跟dns网络配置有关系，最后解决方法是在DNS域名解析的配置文件增加DNS服务器的IP地址：
[root@multi-mysql ~]# vim /etc/resolv.conf
nameserver 8.8.8.8
nameserver 202.106.0.20
注：我只写了第一句就可以了……
重启网络服务
[root@multi-mysql ~]# /etc/init.d/network restart
Shutting down interface eth0: [ OK ]
Shutting down loopback interface: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: Determining if ip address 192.168.1.202 is already in use for device eth0...
[ OK ]
重新yum安装，正常
[root@multi-mysql ~]# yum install nmap -y
Loaded plugins: fastestmirror, security
Loading mirror speeds from cached hostfile
* base: mirrors.yun-idc.com
* extras: mirrors.yun-idc.com
* updates: mirrors.yun-idc.com
base | 3.7 kB 00:00
base/primary_db | 4.6 MB 00:01
extras | 3.4 kB 00:00
extras/primary_db | 33 kB 00:00
updates | 3.4 kB 00:00
updates/primary_db | 2.6 MB 00:00
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package nmap.x86_64 2:5.51-4.el6 will be installed
--> Finished Dependency Resolution
......此处省略