User authentication and logging

One of the major parts of user authentication is to monitor the users of the system. There are various ways to keep a track of all the successful and failed login attempts made by a user in Linux.

Getting ready

Linux system maintains a log of all loginattempts by different accounts in the system. These logs are all located at /var/log/:

 

How to do it...

Linux has many ways to help an administrator to view the logs, both through graphical and command-line methods:

1. If we want to check the incorrect login attempts for a particular user, like root for instance, we can do so by using this command:

lastb root

 

 

 

 

2. To see the log using the Terminal, we use the dmesg command. This command displays the buffer of the Linux kernel's message stored in memory, as shown here:

3. If we wish to filter the preceding output to show only the logs related to USB devices, we can do so by using grep:

4. Instead of viewing all the logs, if we wish to view only the 10 most recent logs in a particular...