Setup Proxy in Linux

For Linux CentOS

  [root@gejoreuy ~]# vi /etc/yum.conf
   ...
  #Add and change the proxy address value below
  proxy=http://10.1.2.3:8080
  proxy=http://10.1.2.4:8080

For Linux Ubuntu

  [root@gejoreuy ~]# vi /etc/apt/apt.conf
   ...
  #Add and change the proxy address value below
  Acquire::http::proxy "http://10.1.2.3:8080/";