Tcpdump parsing for string and sending a notification by email

JoeBloggs1759 · 10-16-2010, 06:30 PM

Hi guy I'm not very good at scripting but here is the problem that I need some scripting help with:

In a particular application when a user ticks a check box (that they shouldn't) the data with the user session information changes enough to break the system:

Bad data: 0x0030 2d33 3238 372d 3100 5450 474c 4f30 3131 -3287-1.TPGLO011

Good data:0x0030 2d33 3238 372d 3101 5450 474c 4f30 3131 -3287-1.TPGLO012

This is from a tcpdump running all the time on a server with lots of disk space using these options:
tcpdump -n -i eth2 -s 0 -w /data/trace7

I then use:
tcpdump -n -r trace6 -s 0 -X -tttt | grep -n -B4 TPGLO | grep -B4 3100

..to find the offending user, in the case above it was TPGLO011 and get them to remove the check box.

We have no control of the users as there are thousands of them around the world. The app is installed and managed locally but the ID is given by us so we can identify them.

How can I automate a script to send an email with that bit of data to the helpdesk....?

x-nc · 10-17-2010, 11:58 AM

Quote:

Originally Posted by JoeBloggs1759

[I]n a particular application when a user ticks a check box (that they shouldn't) the data with the user session information changes enough to break the system:

Bad data: 0x0030 2d33 3238 372d 3100 5450 474c 4f30 3131 -3287-1.TPGLO011

Good data:0x0030 2d33 3238 372d 3101 5450 474c 4f30 3131 -3287-1.TPGLO012

This is from a tcpdump running all the time on a server with lots of disk space using these options:
tcpdump -n -i eth2 -s 0 -w /data/trace7

I then use:
tcpdump -n -r trace6 -s 0 -X -tttt | grep -n -B4 TPGLO | grep -B4 3100

..to find the offending user, in the case above it was TPGLO011 and get them to remove the check box.
[...]
How can I automate a script to send an email with that bit of data to the helpdesk....?

If all the info you need is output from the second tcpdump command then the quickest way would be to pipe the output to mail. Something like thisa -

Code:

tcpdump <stuff> | mail -s "Dumb User" helpdesk@<yoursite>

If you want a more detailed message you can have a text file with instructions for the helpdesk prepared and then append the tcpdump output to it and mail that file. A quick example -

message.template.txt
--------------------
"Dear Helpdesk,

This user is an idiot!

"

script
------

Code:

cp message.template.txt message.txt

tcpdump <stuff> >> message.txt

cat message.txt | mail -s "Dumb User" helpdesk@<yoursite>

That should hopefully get you started.

Joe