TechTip: Email Alert on SSH login
To secure your machine, there are hundred different things you can do, but the most important thing is to know what’s happening on your Machine. In that getting the alerts as soon as someone login is one of very important and must thing to do.
So, to do the same thing, you can go with two approaches:
- Get the alert for some specific users as soon as they login to your machine.
- Get the alert for anyone who successfully logged into your machine.
This is a small script, which you need to put at specific location to get the alerts in much better/presentable shape. Remember to change the values in the sendmail section.
user=`/usr/bin/whoami`
ip=`/usr/bin/last | head -1 | awk ‘{print $3}’`
echo “Subject:SSH Login Alert \n\n User \”$user\” just logged into the machine from IP $ip” | sendmail -F “Sender Name” -f <sender id> <receiver id>
So, to get the alerts we are going to use the above script
- To get alerts when a specific user login to a machine (not all users), just put the script into the User’s home directory. To be specific, just put the script into this file “<User’s home>/.ssh/rc“
- To get the alerts when any user login to the machine, just put the script in ssh config directory. To be specific put the script at “/etc/ssh/sshrc” and you will get the alert as soon as any user login to the machine.
Hope this was helpful.
References:
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let u tel me the relation between inode and the releted file size?
Hi Ravi,
Each and every file under Linux (and UNIX) has following attributes:
> File type (executable, block special etc).
> Permissions (read, write etc).
> Owner
> Group
> File Size.
> File access, change and modification time (remember UNIX or Linux never stores file creation time, this is favorite question asked in UNIX/Linux sys admin job interview).
> File deletion time.
> Number of links (soft/hard).
> Extended attribute such as append only or no one can delete file including root user (immutability).
> Access Control List (ACLs).
All the above information stored in an inode. In short the inode identifies the file and its attributes (as above). Each inode is identified by a unique inode number within the file system. Inode is also know as index number.
I hope this provides you with sufficient information!