The contents of the file /etc/motd  (Message of the Day) are displayed  after a successful login so that you can easily inform  users about displaying warming message to UN-authorized users or display welcome or informational messages to authorized users.

I will make an motd message, there is a program named FIGlet for making large letters. 

Download figlet rpm package then install it .





Then you  add the message what you want to display to users.