I have an issue in mongoDb,

When I am connecting to the mongodb server it never prompts me for the username and password even I have setup an id and password and enabled security authorization in the /etc/mongod.conf file. After I enter the server by typing "mongo" it shows me the available databases but does not let me perform any operations on them.

I want it to ask me for the id and the password whenever I type "mongo" to start the mongoDb server. How should I go about it. I don't want to manually enter the command

mongo -u ******* -p --authenticationDatabase admin
mongo -u ******* -p ********