Solved

In python how can I redirect the output from tcpdump to a variable

Posted on 2015-01-18
2
1,709 Views
Last Modified: 2015-01-19
Greetings,

I am looking for a way to make this work in python,

f=os.system("tcpdump -l src 172.16.0.3 and dst 172.16.0.33")
print "Dump is ", f

I will then process 'f' downstream of this

This produces an output of tcpdump to the console but nothing to the 'f' string

Thanks,
Ron
0
Comment
Question by:RonWensley
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
2 Comments
 
LVL 25

Accepted Solution

by:
clockwatcher earned 500 total points
ID: 40556771
I think you'd be much better served by going with a pcap module (https://code.google.com/p/pypcap/) but you can give this a try:
import StringIO
import sys
import shlex
import subprocess
cmd = "/usr/sbin/tcpdump -l src 172.16.0.3 and dst 172.16.0.33"
args = shlex.split(cmd)
tcpdump = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
print "Press CTRL-C to stop tcpdump"
output = StringIO.StringIO()
running = True
while running:
    try:
        data = tcpdump.stdout.readline()
        if len(data):
            output.write(data)
        else:
            running = False
    except KeyboardInterrupt:
        tcpdump.kill()
        data = tcpdump.stdout.readline()
        if len(data):
            output.write(data)
        running = False

lines = output.getvalue().split("\n")
for i, line in enumerate(lines):
    print "{0} => {1}".format(i, line)

Open in new window

0
 

Author Closing Comment

by:RonWensley
ID: 40558346
Thanks for the quick reply.  This is working out great.  I will have a look at the link you offered and see how that can be used.
0

Featured Post

On Demand Webinar - Networking for the Cloud Era

This webinar discusses:
-Common barriers companies experience when moving to the cloud
-How SD-WAN changes the way we look at networks
-Best practices customers should employ moving forward with cloud migration
-What happens behind the scenes of SteelConnect’s one-click button

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

If you’re thinking to yourself “That description sounds a lot like two people doing the work that one could accomplish,” you’re not alone.
Although it can be difficult to imagine, someday your child will have a career of his or her own. He or she will likely start a family, buy a home and start having their own children. So, while being a kid is still extremely important, it’s also …
Learn several ways to interact with files and get file information from the bash shell. ls lists the contents of a directory: Using the -a flag displays hidden files: Using the -l flag formats the output in a long list: The file command gives us mor…
With the power of JIRA, there's an unlimited number of ways you can customize it, use it and benefit from it. With that in mind, there's bound to be things that I wasn't able to cover in this course. With this summary we'll look at some places to go…

733 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question