Script to email when someone logs into your Linux Systems

This is a great script to use on Linux servers that you really want to know who has been logging into them e.g. Public web servers or critical systems. It can also aid in the process of change management.

Code:

echo 'Login on' `hostname` `date` `who` | mail -s "Login on `hostname` `who | sort -k 3,4 -r | head -1 | awk '{print $5}'`" [email protected]

Place this code in your /etc/profile file on a Debian based system.

Reference: Linux Magazine
http://www.linux-magazine.com/Issues/2010/117/SPYGLASS

Are Jumbo Frames working?

Do you have Jumbo frame configured? Are they working?

In your VM, ping your destination with a large message and specify don’t fragment.

  • Linux                  ping –M do –s 8000 <ip address or destination>
  • Windows             ping –f –l 8000 <ip address or destination>
  • ESX(i):                vmkping –d –s 8000 <ip address or destination>