This is a useful hack for VPS servers to send an email as a login-notify to an email address.

Prerequisites

You need to have a working mail subsystem on your host so that the mail command works.

This works with Ubuntu 22.04 and later versions.

Modify PAM to notify on login

Open the file /etc/pam.d/common-session and at the bottom add the following line:

session optional pam_exec.so /root/script/login-notify

Login-Notify script

Create the following script in /root/script/login-notify

#!/bin/bash                                                                                
                                                                                           
#                                                                                          
# This script is run by PAM from /etc/pam.d/common-session by adding the following         
# line to the bottom of the configuration file:                                            
#                                                                                          
# session optional pam_exec.so /root/script/login-notify                                   
#                                                                                          
# Make sure the script is executeable                                                      
#                                                                                          
# ichi@ichimusai.org                                                                       
# Revision 1.0.0                                                                           
#                                                                                          
                                                                                           
                                                                                           
[ "$PAM_TYPE" = "open_session" ] || exit 0                                                 
{                                                                                          
    echo "User:    $PAM_USER"                                                              
    echo "Ruser:   $PAM_RUSER"                                                             
    echo "Rhost:   $PAM_RHOST"                                                             
    echo "Service: $PAM_SERVICE"                                                           
    echo "TTY:     $PAM_TTY"                                                               
    echo "Date:    `date +"%y%m%d-%H%M%S"`"                                                
    echo "Server:  `hostname -s`"                                                          
} | mail -s "[`hostname -s`] $PAM_SERVICE login: $PAM_USER" anders@sikvall.se &                                                                                

This script will now be executed upon login and should send an email to the recipient with login matters.