As a server administrator, you should check last login history to identify whoever logged into the system recently.
Linux is a multi-user operating system and more than one user can be logged into a system at the same time.
It’s keeping bunch of useful information about the users activity such as username, name of the terminal connected, source IP, date and time.
Also, it will show you how long the user being logged into the system.
It will help us to analyze some of the issues. Say for example, if some files get removed in the particular time then we can ask the users whoever logged into the system on the particular time.
Alternatively, we can check these information using aureport tool that produces summary reports of the audit system logs.
Similarly we can use these information for other purpose as well. Is there any anonymous login attempts are found or not.
Also, from which IP address the user has accessed the system.
These information (last login, current login and bad login attempts) can be fetched from the following files.
utmp & wtmp files contains logs for login and logout. These are binary files and we can’t able to see with any text editor.
It’s located on /etc/log directory.
- /var/run/utmp: It contains information about the users who are currently logged onto the system. Who command is used to fetch the information from the file.
- /var/log/wtmp: It contains historical utmp. It keeps the users login and logout history. The last command uses this file to display the information.
- /var/log/btmp: It contains bad login attempts.
What Is last Command?
Last searches back through the file /var/log/wtmp and displays a list of all users logged in (and out) since that file was created.
What Is lastb Command?
Lastb is the same as last, except that by default it shows a log of the file /var/log/btmp, which contains all the bad login attempts.
Difference between pts and tty?
You may see pts and tty when you use the who command, do you know what it is? how they are different?
- A tty is a native terminal device (It could be a server/system console).
- A pty (pseudo terminal device) is a terminal device which is emulated by an other program such as putty, xterm or screen, etc,.
How To Check Login History In Linux Using last Command?
The last command fetch the details from the /var/log/wtmp file and it displays the list of users logged-in and logged-out from system.
If the file has more data then use less or more command to view the information page wise.
How To Check Login History For Particular User In Linux Using last Command?
Just add the desired user name followed by the last command to get the details.
How To Check Login History For Particular Period In Linux Using last Command?
If you would like to check who was logged in the system for particular period then use the following format.
For Particular user, use the following format.
How To Check Login History Based On Terminal Connected In Linux Using last Command?
To print the user based on the terminal connected. Use the following format.
How To Check Bad Login History In Linux Using lastb Command?
Lastb is the same as last but it will print the bad login attempts. Since the output was archived in the different file so, i have picked the corresponding file to check the details.
Run the following format to display hostnames in the last column.
Run the following format to suppress the hostname field.
Run the following format to display system shutdown entries and run level changes.
Alternatively, this can be verified via /var/log/secure and /var/log/auth.log file.
For RHEL based systems.
For Ubuntu based systems.
For failed attempts.
The lastlog command reports the most recent login of all users. This is very useful if you would like to check which users are not login the server more than 30 to 60 days.
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