Solved

tcpdump time filter

Posted on 2009-04-08
6
1,507 Views
Last Modified: 2014-06-17
Let's say I have a tcpdump file. Is there a way to only print packets that has arrived after a certain time? Capture file contains traffic from 1pm to 7pm. I want to print all packets after 5pm. Like...

tcpdump -nr source.cap time >= 17:00

I'm trying to use this in a script. Thanks.
0
Comment
Question by:zyca
  • 2
6 Comments
 
LVL 61

Expert Comment

by:gheist
ID: 24124825
Start your script in particular time. tcpdump is not scheduler.
0
 

Accepted Solution

by:
RickAtreides earned 168 total points
ID: 25040601
tcpdump has no ability to filter packets by timestamp, so you should filter output with some script like

sudo tcpdump -i eth0  | ./filter-time.pl '17:00:00' 22:00:00'

Please note, that tcpdump's output didn't contain day part, so you should care about time ranges over midnight like 23:00 -> 01:00.
#!/usr/bin/perl
 

# Convert time range to seconds from midnight

$ARGV[0] =~ /(\d{2}):(\d{2}):(\d{2})/;

$begin_t = $3 + 60 * $2 + 60 * 60 * $1;

$ARGV[1] =~ /(\d{2}):(\d{2}):(\d{2})/;

$end_t = $3 + 60 * $2 + 60 * 60 * $1;
 

while (<STDIN>) {

 # If row begin with time stamp 

 if (/^(\d{2}):(\d{2}):(\d{2}).\d{6}/) {

   $time = $3 + 60 * $2 + 60 * 60 * $1;

   # We make decision is it packet in range or not

   if ($time <= $end_t && $time >= $begin_t) {

    $print_packet=1

   } else {

    $print_packet=0

   }

 }
 

 if ($print_packet) { print $_ }

}

Open in new window

0
 
LVL 61

Assisted Solution

by:gheist
gheist earned 166 total points
ID: 25040938
wireshark includes command line capture file converter that does what you beg for.
0
 
LVL 5

Assisted Solution

by:group0
group0 earned 166 total points
ID: 33431731
Run it through Wireshark and use a filter in the format:

frame.time >= "Aug 4, 2010 17:00:00"
0

Featured Post

Microsoft Certification Exam 74-409

Veeam® is happy to provide the Microsoft community with a study guide prepared by MVP and MCT, Orin Thomas. This guide will take you through each of the exam objectives, helping you to prepare for and pass the examination.

Question has a verified solution.

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

Suggested Solutions

Title # Comments Views Activity
Cisco RSTP portfast 3 49
Sonicwall TZ 205- Dropping Incoming E-mail as IP Spoof 13 87
Botnet detection help me please 21 78
VIRTUAL NETWORKING 3 23
Even if you have implemented a Mobile Device Management solution company wide, it is a good idea to make sure you are taking into account all of the major risks to your electronic protected health information (ePHI).
ADCs have gained traction within the last decade, largely due to increased demand for legacy load balancing appliances to handle more advanced application delivery requirements and improve application performance.
Get a first impression of how PRTG looks and learn how it works.   This video is a short introduction to PRTG, as an initial overview or as a quick start for new PRTG users.
In this tutorial you'll learn about bandwidth monitoring with flows and packet sniffing with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're interested in additional methods for monitoring bandwidt…

932 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

Need Help in Real-Time?

Connect with top rated Experts

10 Experts available now in Live!

Get 1:1 Help Now