Restrict maximum simultaneous logins on Linux

Want to restrict simultaneous number of logins attempt on Linux machine? Here is the quick way of doing it.

1. Edit the file /etc/security/limits.conf to make the below changes:

#cat /etc/security/limits.conf

# /etc/security/limits.conf
#
#Each line describes a limit for a user in the form:
#
#
#
#Where:
# can be:
# - an user name
# - a group name, with @group syntax
# - the wildcard *, for default entry
# - the wildcard %, can be also used with %group syntax,
# for maxlogin limit
# - NOTE: group and wildcard limits are not applied to root.
# To apply a limit to the root user, must be
# the literal username root.
#
# can have the two values:
# - "soft" for enforcing the soft limits
# - "hard" for enforcing hard limits
#
# can be one of the following:
# - core - limits the core file size (KB)
# - data - max data size (KB)
# - fsize - maximum filesize (KB)
# - memlock - max locked-in-memory address space (KB)
# - nofile - max number of open files
# - rss - max resident set size (KB)
# - stack - max stack size (KB)
# - cpu - max CPU time (MIN)
# - nproc - max number of processes
# - as - address space limit (KB)
# - maxlogins - max number of logins for this user
# - maxsyslogins - max number of logins on the system
# - priority - the priority to run user process with
# - locks - max number of file locks the user can hold
# - sigpending - max number of pending signals
# - msgqueue - max memory used by POSIX message queues (bytes)
# - nice - max nice priority allowed to raise to values: [-20, 19]
# - rtprio - max realtime priority
# - chroot - change root to directory (Debian-specific)
#
#
#