I‘m running RHEL on HP server. This server allows to login to reset of the LAN from the Internet. How do I find out failed login records under Linux operating systems?

You need to use the faillog command to see the all failed login attempts. Linux records failed login into a special database at /var/log/faillog. To see contents of the failure log database at /var/log/faillog use faillog command. The same command can be used for

1. Set the failure counters.
2. Set or configure the limits.
3. Display failed login information.

More About /var/log/faillog File

The /var/log/faillog maintains a count of login failures and the limits for each account. The file is binary format with the following the structure of the file:

           struct    faillog {
                short   fail_cnt;
                short   fail_max;
                char    fail_line[12];
                time_t  fail_time;
                long    fail_locktime;
           };

You cannot view the structure using the cat command:
# cat /var/log/faillog
So you need to use the faillog command to display this binary file records.

faillog Command Examplesdescribed in our previous tutorial. To display failed login attempts for user tom, enter:
# faillog -u usernameHere
# faillog -u tom
To display failed login attempts for all users, enter:
# faillog -a
To display faillog records more recent than 5 days, enter:
# faillog -t 5 -u tom

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin and a trainer for the Linux operating system/Unix shell scripting. He has worked with global clients and in various industries, including IT, education, defense and space research, and the nonprofit sector. Follow him on Twitter, Facebook, Google+.