yum install wget Enter when you look wrong

Recent review of Linux knowledge, feels there is still a lot of problems occur problem of finishing are as follows:
1, in the mini version of CentOS is via vitrualbox installed, install lnmp environment need to yum install wget
On the command line, type yum install wget error occurred when carriage return:
After Google and Bing search and verify that turn out to be because the DNS configuration errors caused by DNS is not configured in the configuration file. Need to modify the following 2 sites:
1) vi /etc/sysconfig/network-scripts/ifcfg-eth0
Modify ONBOOT=yes MM_CONTROLLED=no these 2 options
Save and then restart the network service network restart
2) need to write/resolve.conf default is an empty file contents
Can be used by adding a DNS, nameserver DNS IP address and then save
Finally restart CentOS system under normal use