1. Open the /etc/pam.d/system-auth file for editing.
ensure that a backup done for the file which you are editing.
2. Add the following lines:
auth required pam_tally.so no_magic_root
account required pam_tally.so deny=2 no_magic_root
here the value of deny implies how many login attempts should faillog wait before locking the account for login.
3. Save the file and exit.
4. Test the configuration by attempting to login as a normal user, but using a wrong password.
5. Verify the failed count increments by running the command:
6. To disable faillog for one particular user faillog -m -1 -u username