Login Sequence in AIX

How the login takes place in AIX?

You need to download and install putty to connect to the server if the server is remotely available. You need to mention the ip address, port number and connection type (telnet, SSH, rlogin etc) and connect to the server.

Once connected, the black session screen will appear/open up and will ask for user to login (settings available in /etc/security/login.cfg ).

Login sequence:

1. As the user enters the username and password, system verifies the same from /etc/passwd and/etc/security/passwd file.
2. If valid, the user is logged into the system else the user is asked to re-enter the username and password on every invalid entry (records a log entry in /etc/security/failedlogin).
3. Once logged in, the system setup user’s environment. This is available in /etc/environment, /etc/security/environment, /etc/security/user, /etc/security/limits.
4. It sometimes displays the “Message of the Day” configured by the administrator on login. This is available in /etc/motd? File.
5. Login shell will appear.
6. User’s profile (/etc/profile) will be setup and user will be placed in HOME directory.

Now the user can run any commands on the screen.

So the main steps for users to login are:

Login -> /etc/environment -> /etc/profile -> HOME directory