全局代理配置，yum和wget都可以成功上網
vi /etc/profile http_proxy=http://test:[email protected]:808/ https_proxy=http://test:[email protected]:808/ export http_proxy export https_proxy
source /etc/profile
yum代理配置，只有yum可以成功上網
vi /etc/yum.conf proxy=http://172.18.55.100:808 proxy_username=test proxy_password=123456