linux-free secret login and set the alias

First, avoid close Login

　　(1) Public key configuration

　　　　  ssh-keygen 

      (2) allows a remote server to remember the public key

　　　　  ssh-copy-id user name @ip address or domain name

Second, set the alias

      (3) Create and edit config files under ~ / .ssh directory

　　　　  vim config(centos)

　　　　  vim config(ubuntu)

　   (4) config file contents

　　　　  Host Host name

       　　 　　HostName ip address

       　　 　　User Username

　　　　　　  Port Port

Annex: ssh-keygen command input after all the way round to

      After alias setup is complete, you can log in using ssh + free dense hostname