The Red Hat Linux System provides the different ways of protecting your computer system like Password protection, Network filtering, and Security audits.

Password Protection: This is one of the most fundamental security tools of any operating system. Choosing good passwords is the first and most necessary step for having a secure system.

The following points are to be avoided when choosing a password:

• Do not use any variation of your login name or your full name.
• Do not use a dictionary word.
• Do not use proper names of any kind.
• Do not use any contiguous letters on the keyboard.

You may change your password periodically. It is even possible to set an expiration date of Linux password by using the change command to change the expiration date of password on your Red Hat Linux System.For example: To set the password expiration so that user RajCev is prompted to change his password every 30 days, you would log in as root and type the following command:

#change – M 30 Rajeev

Here M parameter tells the change command that you are setting the maximum number of days to keep the password. Setting the Root Password: The installation program will prompt you to set a root password for your system. The root password must be of minimum six characters long, the password you type is not echoed to the screen. You must enter a password twice, and if both the passwords couldn’t match, the installation program will ask you to enter them again. Remember that the password is case sensitive. Write down the password and keep it in a secure place.

The root user has complete access to the entire system. For this reason, logging in as the root user is best done only to perform system maintenance or administration.